diff --git a/CHANGELOG.md b/CHANGELOG.md
index dceef247..68cce41c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -57,9 +57,17 @@
 
 ### Changed
 
+- @cosmjs/encoding: Change return type of `fromRfc3339` from `ReadonlyDate` to
+  `Date` as the caller becomes the owner of the object and can safely mutate it
+  in any way.
 - @cosmjs/launchpad-ledger: Renamed to @cosmjs/ledger-amino.
 - @cosmjs/ledger-amino: `LedgerSigner.sign` method renamed `signAmino`.
 
+### Deprecated
+
+- @cosmjs/tendermint-rpc: Deprecate `DateTime` in favour of the free functions
+  `fromRfc3339WithNanoseconds` and `toRfc3339WithNanoseconds`.
+
 ## 0.23.2 (2021-01-06)
 
 ### Security
diff --git a/packages/cosmwasm-stargate/src/cosmwasmclient.ts b/packages/cosmwasm-stargate/src/cosmwasmclient.ts
index 8b15dc71..d5d267c0 100644
--- a/packages/cosmwasm-stargate/src/cosmwasmclient.ts
+++ b/packages/cosmwasm-stargate/src/cosmwasmclient.ts
@@ -35,7 +35,7 @@ import {
   adaptor34,
   broadcastTxCommitSuccess,
   Client as TendermintClient,
-  DateTime,
+  toRfc3339WithNanoseconds,
 } from "@cosmjs/tendermint-rpc";
 import { assert } from "@cosmjs/utils";
 
@@ -114,7 +114,7 @@ export class CosmWasmClient {
         },
         height: response.block.header.height,
         chainId: response.block.header.chainId,
-        time: DateTime.encode(response.block.header.time),
+        time: toRfc3339WithNanoseconds(response.block.header.time),
       },
       txs: response.block.txs,
     };
diff --git a/packages/encoding/src/rfc3339.ts b/packages/encoding/src/rfc3339.ts
index 1b58fe14..180ee995 100644
--- a/packages/encoding/src/rfc3339.ts
+++ b/packages/encoding/src/rfc3339.ts
@@ -7,7 +7,7 @@ function padded(integer: number, length = 2): string {
   return filled.substring(filled.length - length);
 }
 
-export function fromRfc3339(str: string): ReadonlyDate {
+export function fromRfc3339(str: string): Date {
   const matches = rfc3339Matcher.exec(str);
   if (!matches) {
     throw new Error("Date string is not in RFC3339 format");
@@ -40,9 +40,8 @@ export function fromRfc3339(str: string): ReadonlyDate {
 
   const tzOffset = tzOffsetSign * (tzOffsetHours * 60 + tzOffsetMinutes) * 60; // seconds
 
-  return new ReadonlyDate(
-    ReadonlyDate.UTC(year, month - 1, day, hour, minute, second, milliSeconds) - tzOffset * 1000,
-  );
+  const timestamp = Date.UTC(year, month - 1, day, hour, minute, second, milliSeconds) - tzOffset * 1000;
+  return new Date(timestamp);
 }
 
 export function toRfc3339(date: Date | ReadonlyDate): string {
diff --git a/packages/stargate/src/stargateclient.ts b/packages/stargate/src/stargateclient.ts
index bc26a5a7..8b6c5b4b 100644
--- a/packages/stargate/src/stargateclient.ts
+++ b/packages/stargate/src/stargateclient.ts
@@ -15,7 +15,7 @@ import {
   adaptor34,
   broadcastTxCommitSuccess,
   Client as TendermintClient,
-  DateTime,
+  toRfc3339WithNanoseconds,
 } from "@cosmjs/tendermint-rpc";
 import { assert, assertDefinedAndNotNull } from "@cosmjs/utils";
 import Long from "long";
@@ -185,7 +185,7 @@ export class StargateClient {
         },
         height: response.block.header.height,
         chainId: response.block.header.chainId,
-        time: DateTime.encode(response.block.header.time),
+        time: toRfc3339WithNanoseconds(response.block.header.time),
       },
       txs: response.block.txs,
     };
diff --git a/packages/tendermint-rpc/src/adaptors/v0-33/hasher.spec.ts b/packages/tendermint-rpc/src/adaptors/v0-33/hasher.spec.ts
index cc3081b2..a9f0c4c5 100644
--- a/packages/tendermint-rpc/src/adaptors/v0-33/hasher.spec.ts
+++ b/packages/tendermint-rpc/src/adaptors/v0-33/hasher.spec.ts
@@ -1,7 +1,7 @@
 import { fromBase64, fromHex } from "@cosmjs/encoding";
 import { ReadonlyDate } from "readonly-date";
 
-import { ReadonlyDateWithNanoseconds } from "../../types";
+import { ReadonlyDateWithNanoseconds } from "../../dates";
 import { hashBlock, hashTx } from "./hasher";
 
 describe("Hasher", () => {
diff --git a/packages/tendermint-rpc/src/adaptors/v0-33/responses.ts b/packages/tendermint-rpc/src/adaptors/v0-33/responses.ts
index 02f7355f..b2d6a297 100644
--- a/packages/tendermint-rpc/src/adaptors/v0-33/responses.ts
+++ b/packages/tendermint-rpc/src/adaptors/v0-33/responses.ts
@@ -3,6 +3,7 @@ import { fromBase64, fromHex } from "@cosmjs/encoding";
 import { JsonRpcSuccessResponse } from "@cosmjs/json-rpc";
 import { assert } from "@cosmjs/utils";
 
+import { fromRfc3339WithNanoseconds } from "../../dates";
 import {
   assertArray,
   assertBoolean,
@@ -11,7 +12,6 @@ import {
   assertObject,
   assertSet,
   assertString,
-  DateTime,
   dictionaryToStringMap,
   Integer,
   may,
@@ -328,7 +328,7 @@ function decodeHeader(data: RpcHeader): responses.Header {
     version: decodeBlockVersion(data.version),
     chainId: assertNotEmpty(data.chain_id),
     height: Integer.parse(assertNotEmpty(data.height)),
-    time: DateTime.decode(assertNotEmpty(data.time)),
+    time: fromRfc3339WithNanoseconds(assertNotEmpty(data.time)),
 
     lastBlockId: decodeBlockId(data.last_block_id),
 
@@ -417,7 +417,7 @@ function decodeCommitSignature(data: RpcSignature): CommitSignature {
   return {
     blockIdFlag: decodeBlockIdFlag(data.block_id_flag),
     validatorAddress: fromHex(data.validator_address),
-    timestamp: DateTime.decode(assertNotEmpty(data.timestamp)),
+    timestamp: fromRfc3339WithNanoseconds(assertNotEmpty(data.timestamp)),
     signature: fromBase64(assertNotEmpty(data.signature)),
   };
 }
@@ -488,7 +488,7 @@ interface GenesisResult {
 
 function decodeGenesis(data: RpcGenesisResponse): responses.GenesisResponse {
   return {
-    genesisTime: DateTime.decode(assertNotEmpty(data.genesis_time)),
+    genesisTime: fromRfc3339WithNanoseconds(assertNotEmpty(data.genesis_time)),
     chainId: assertNotEmpty(data.chain_id),
     consensusParams: decodeConsensusParams(data.consensus_params),
     validators: data.validators ? assertArray(data.validators).map(decodeValidatorGenesis) : [],
@@ -568,7 +568,7 @@ function decodeSyncInfo(data: RpcSyncInfo): responses.SyncInfo {
   return {
     latestBlockHash: fromHex(assertNotEmpty(data.latest_block_hash)),
     latestAppHash: fromHex(assertNotEmpty(data.latest_app_hash)),
-    latestBlockTime: DateTime.decode(assertNotEmpty(data.latest_block_time)),
+    latestBlockTime: fromRfc3339WithNanoseconds(assertNotEmpty(data.latest_block_time)),
     latestBlockHeight: Integer.parse(assertNotEmpty(data.latest_block_height)),
     catchingUp: assertBoolean(data.catching_up),
   };
diff --git a/packages/tendermint-rpc/src/dates.spec.ts b/packages/tendermint-rpc/src/dates.spec.ts
new file mode 100644
index 00000000..dfdf0b94
--- /dev/null
+++ b/packages/tendermint-rpc/src/dates.spec.ts
@@ -0,0 +1,90 @@
+import { ReadonlyDate } from "readonly-date";
+
+import { DateTime, DateWithNanoseconds, fromRfc3339WithNanoseconds, toRfc3339WithNanoseconds } from "./dates";
+
+describe("dates", () => {
+  describe("fromRfc3339WithNanoseconds", () => {
+    it("works", () => {
+      expect(fromRfc3339WithNanoseconds("2020-12-15T10:57:26.778Z").nanoseconds).toEqual(0);
+      expect(fromRfc3339WithNanoseconds("2020-12-15T10:57:26.7789Z").nanoseconds).toEqual(900000);
+      expect(fromRfc3339WithNanoseconds("2020-12-15T10:57:26.77809Z").nanoseconds).toEqual(90000);
+      expect(fromRfc3339WithNanoseconds("2020-12-15T10:57:26.778009Z").nanoseconds).toEqual(9000);
+      expect(fromRfc3339WithNanoseconds("2020-12-15T10:57:26.7780009Z").nanoseconds).toEqual(900);
+      expect(fromRfc3339WithNanoseconds("2020-12-15T10:57:26.77800009Z").nanoseconds).toEqual(90);
+      expect(fromRfc3339WithNanoseconds("2020-12-15T10:57:26.778000009Z").nanoseconds).toEqual(9);
+    });
+  });
+
+  describe("toRfc3339WithNanoseconds", () => {
+    it("works", () => {
+      const date1 = new ReadonlyDate("2020-12-15T10:57:26.778Z");
+      (date1 as any).nanoseconds = 0;
+      expect(toRfc3339WithNanoseconds(date1)).toEqual("2020-12-15T10:57:26.778000000Z");
+      const date2 = new ReadonlyDate("2020-12-15T10:57:26.778Z");
+      (date2 as any).nanoseconds = 900000;
+      expect(toRfc3339WithNanoseconds(date2)).toEqual("2020-12-15T10:57:26.778900000Z");
+      const date3 = new ReadonlyDate("2020-12-15T10:57:26.778Z");
+      (date3 as any).nanoseconds = 90000;
+      expect(toRfc3339WithNanoseconds(date3)).toEqual("2020-12-15T10:57:26.778090000Z");
+      const date4 = new ReadonlyDate("2020-12-15T10:57:26.778Z");
+      (date4 as any).nanoseconds = 9000;
+      expect(toRfc3339WithNanoseconds(date4)).toEqual("2020-12-15T10:57:26.778009000Z");
+      const date5 = new ReadonlyDate("2020-12-15T10:57:26.778Z");
+      (date5 as any).nanoseconds = 900;
+      expect(toRfc3339WithNanoseconds(date5)).toEqual("2020-12-15T10:57:26.778000900Z");
+      const date6 = new ReadonlyDate("2020-12-15T10:57:26.778Z");
+      (date6 as any).nanoseconds = 90;
+      expect(toRfc3339WithNanoseconds(date6)).toEqual("2020-12-15T10:57:26.778000090Z");
+      const date7 = new ReadonlyDate("2020-12-15T10:57:26.778Z");
+      (date7 as any).nanoseconds = 9;
+      expect(toRfc3339WithNanoseconds(date7)).toEqual("2020-12-15T10:57:26.778000009Z");
+    });
+
+    it("works for DateWithNanoseconds", () => {
+      const date1: DateWithNanoseconds = new Date("2020-12-15T10:57:26.778Z");
+      date1.nanoseconds = 1;
+      expect(toRfc3339WithNanoseconds(date1)).toEqual("2020-12-15T10:57:26.778000001Z");
+    });
+
+    it("works for Date", () => {
+      const date1 = new Date("2020-12-15T10:57:26.778Z");
+      expect(toRfc3339WithNanoseconds(date1)).toEqual("2020-12-15T10:57:26.778000000Z");
+    });
+  });
+
+  describe("DateTime", () => {
+    it("decodes a string", () => {
+      expect(DateTime.decode("2020-12-15T10:57:26.778Z").nanoseconds).toEqual(0);
+      expect(DateTime.decode("2020-12-15T10:57:26.7789Z").nanoseconds).toEqual(900000);
+      expect(DateTime.decode("2020-12-15T10:57:26.77809Z").nanoseconds).toEqual(90000);
+      expect(DateTime.decode("2020-12-15T10:57:26.778009Z").nanoseconds).toEqual(9000);
+      expect(DateTime.decode("2020-12-15T10:57:26.7780009Z").nanoseconds).toEqual(900);
+      expect(DateTime.decode("2020-12-15T10:57:26.77800009Z").nanoseconds).toEqual(90);
+      expect(DateTime.decode("2020-12-15T10:57:26.778000009Z").nanoseconds).toEqual(9);
+    });
+
+    it("encodes a string", () => {
+      const date1 = new ReadonlyDate("2020-12-15T10:57:26.778Z");
+      (date1 as any).nanoseconds = 0;
+      expect(DateTime.encode(date1)).toEqual("2020-12-15T10:57:26.778000000Z");
+      const date2 = new ReadonlyDate("2020-12-15T10:57:26.778Z");
+      (date2 as any).nanoseconds = 900000;
+      expect(DateTime.encode(date2)).toEqual("2020-12-15T10:57:26.778900000Z");
+      const date3 = new ReadonlyDate("2020-12-15T10:57:26.778Z");
+      (date3 as any).nanoseconds = 90000;
+      expect(DateTime.encode(date3)).toEqual("2020-12-15T10:57:26.778090000Z");
+      const date4 = new ReadonlyDate("2020-12-15T10:57:26.778Z");
+      (date4 as any).nanoseconds = 9000;
+      expect(DateTime.encode(date4)).toEqual("2020-12-15T10:57:26.778009000Z");
+      const date5 = new ReadonlyDate("2020-12-15T10:57:26.778Z");
+      (date5 as any).nanoseconds = 900;
+      expect(DateTime.encode(date5)).toEqual("2020-12-15T10:57:26.778000900Z");
+      const date6 = new ReadonlyDate("2020-12-15T10:57:26.778Z");
+      (date6 as any).nanoseconds = 90;
+      expect(DateTime.encode(date6)).toEqual("2020-12-15T10:57:26.778000090Z");
+      const date7 = new ReadonlyDate("2020-12-15T10:57:26.778Z");
+      (date7 as any).nanoseconds = 9;
+      expect(DateTime.encode(date7)).toEqual("2020-12-15T10:57:26.778000009Z");
+    });
+  });
+});
diff --git a/packages/tendermint-rpc/src/dates.ts b/packages/tendermint-rpc/src/dates.ts
new file mode 100644
index 00000000..4a15ccfc
--- /dev/null
+++ b/packages/tendermint-rpc/src/dates.ts
@@ -0,0 +1,39 @@
+import { fromRfc3339 } from "@cosmjs/encoding";
+import { ReadonlyDate } from "readonly-date";
+
+export interface ReadonlyDateWithNanoseconds extends ReadonlyDate {
+  /* Nanoseconds after the time stored in a vanilla ReadonlyDate (millisecond granularity) */
+  readonly nanoseconds?: number;
+}
+
+export interface DateWithNanoseconds extends Date {
+  /** Nanoseconds after the time stored in a vanilla Date (millisecond granularity) */
+  nanoseconds?: number;
+}
+
+export function fromRfc3339WithNanoseconds(dateTimeString: string): DateWithNanoseconds {
+  const out: DateWithNanoseconds = fromRfc3339(dateTimeString);
+  const nanosecondsMatch = dateTimeString.match(/\.(\d+)Z$/);
+  const nanoseconds = nanosecondsMatch ? nanosecondsMatch[1].slice(3) : "";
+  out.nanoseconds = parseInt(nanoseconds.padEnd(6, "0"), 10);
+  return out;
+}
+
+export function toRfc3339WithNanoseconds(dateTime: ReadonlyDateWithNanoseconds): string {
+  const millisecondIso = dateTime.toISOString();
+  const nanoseconds = dateTime.nanoseconds?.toString() ?? "";
+  return `${millisecondIso.slice(0, -1)}${nanoseconds.padStart(6, "0")}Z`;
+}
+
+/** @deprecated Use fromRfc3339WithNanoseconds/toRfc3339WithNanoseconds instead */
+export class DateTime {
+  /** @deprecated Use fromRfc3339WithNanoseconds instead */
+  public static decode(dateTimeString: string): ReadonlyDateWithNanoseconds {
+    return fromRfc3339WithNanoseconds(dateTimeString);
+  }
+
+  /** @deprecated Use toRfc3339WithNanoseconds instead */
+  public static encode(dateTime: ReadonlyDateWithNanoseconds): string {
+    return toRfc3339WithNanoseconds(dateTime);
+  }
+}
diff --git a/packages/tendermint-rpc/src/encodings.spec.ts b/packages/tendermint-rpc/src/encodings.spec.ts
index 88750e68..afea0600 100644
--- a/packages/tendermint-rpc/src/encodings.spec.ts
+++ b/packages/tendermint-rpc/src/encodings.spec.ts
@@ -1,53 +1,8 @@
 import { ReadonlyDate } from "readonly-date";
 
-import {
-  DateTime,
-  encodeBlockId,
-  encodeBytes,
-  encodeInt,
-  encodeString,
-  encodeTime,
-  encodeVersion,
-} from "./encodings";
-import { ReadonlyDateWithNanoseconds } from "./types";
+import { encodeBlockId, encodeBytes, encodeInt, encodeString, encodeTime, encodeVersion } from "./encodings";
 
 describe("encodings", () => {
-  describe("DateTime", () => {
-    it("decodes a string", () => {
-      expect(DateTime.decode("2020-12-15T10:57:26.778Z").nanoseconds).toEqual(0);
-      expect(DateTime.decode("2020-12-15T10:57:26.7789Z").nanoseconds).toEqual(900000);
-      expect(DateTime.decode("2020-12-15T10:57:26.77809Z").nanoseconds).toEqual(90000);
-      expect(DateTime.decode("2020-12-15T10:57:26.778009Z").nanoseconds).toEqual(9000);
-      expect(DateTime.decode("2020-12-15T10:57:26.7780009Z").nanoseconds).toEqual(900);
-      expect(DateTime.decode("2020-12-15T10:57:26.77800009Z").nanoseconds).toEqual(90);
-      expect(DateTime.decode("2020-12-15T10:57:26.778000009Z").nanoseconds).toEqual(9);
-    });
-
-    it("encodes a string", () => {
-      const date1 = new ReadonlyDate("2020-12-15T10:57:26.778Z") as ReadonlyDateWithNanoseconds;
-      (date1 as any).nanoseconds = 0;
-      expect(DateTime.encode(date1)).toEqual("2020-12-15T10:57:26.778000000Z");
-      const date2 = new ReadonlyDate("2020-12-15T10:57:26.778Z") as ReadonlyDateWithNanoseconds;
-      (date2 as any).nanoseconds = 900000;
-      expect(DateTime.encode(date2)).toEqual("2020-12-15T10:57:26.778900000Z");
-      const date3 = new ReadonlyDate("2020-12-15T10:57:26.778Z") as ReadonlyDateWithNanoseconds;
-      (date3 as any).nanoseconds = 90000;
-      expect(DateTime.encode(date3)).toEqual("2020-12-15T10:57:26.778090000Z");
-      const date4 = new ReadonlyDate("2020-12-15T10:57:26.778Z") as ReadonlyDateWithNanoseconds;
-      (date4 as any).nanoseconds = 9000;
-      expect(DateTime.encode(date4)).toEqual("2020-12-15T10:57:26.778009000Z");
-      const date5 = new ReadonlyDate("2020-12-15T10:57:26.778Z") as ReadonlyDateWithNanoseconds;
-      (date5 as any).nanoseconds = 900;
-      expect(DateTime.encode(date5)).toEqual("2020-12-15T10:57:26.778000900Z");
-      const date6 = new ReadonlyDate("2020-12-15T10:57:26.778Z") as ReadonlyDateWithNanoseconds;
-      (date6 as any).nanoseconds = 90;
-      expect(DateTime.encode(date6)).toEqual("2020-12-15T10:57:26.778000090Z");
-      const date7 = new ReadonlyDate("2020-12-15T10:57:26.778Z") as ReadonlyDateWithNanoseconds;
-      (date7 as any).nanoseconds = 9;
-      expect(DateTime.encode(date7)).toEqual("2020-12-15T10:57:26.778000009Z");
-    });
-  });
-
   describe("encodeString", () => {
     it("works", () => {
       expect(encodeString("")).toEqual(Uint8Array.from([0]));
diff --git a/packages/tendermint-rpc/src/encodings.ts b/packages/tendermint-rpc/src/encodings.ts
index 59f6e042..ef7727ee 100644
--- a/packages/tendermint-rpc/src/encodings.ts
+++ b/packages/tendermint-rpc/src/encodings.ts
@@ -1,8 +1,8 @@
-import { fromRfc3339, toUtf8 } from "@cosmjs/encoding";
+import { toUtf8 } from "@cosmjs/encoding";
 import { Int53 } from "@cosmjs/math";
 
+import { ReadonlyDateWithNanoseconds } from "./dates";
 import { BlockId, Version } from "./responses";
-import { ReadonlyDateWithNanoseconds } from "./types";
 
 /**
  * A runtime checker that ensures a given value is set (i.e. not undefined or null)
@@ -156,22 +156,6 @@ export class Integer {
   }
 }
 
-export class DateTime {
-  public static decode(dateTimeString: string): ReadonlyDateWithNanoseconds {
-    const readonlyDate = fromRfc3339(dateTimeString);
-    const nanosecondsMatch = dateTimeString.match(/\.(\d+)Z$/);
-    const nanoseconds = nanosecondsMatch ? nanosecondsMatch[1].slice(3) : "";
-    (readonlyDate as any).nanoseconds = parseInt(nanoseconds.padEnd(6, "0"), 10);
-    return readonlyDate as ReadonlyDateWithNanoseconds;
-  }
-
-  public static encode(dateTime: ReadonlyDateWithNanoseconds): string {
-    const millisecondIso = dateTime.toISOString();
-    const nanoseconds = dateTime.nanoseconds?.toString() ?? "";
-    return `${millisecondIso.slice(0, -1)}${nanoseconds.padStart(6, "0")}Z`;
-  }
-}
-
 // Encodings needed for hashing block headers
 // Several of these functions are inspired by https://github.com/nomic-io/js-tendermint/blob/tendermint-0.30/src/
 
diff --git a/packages/tendermint-rpc/src/index.ts b/packages/tendermint-rpc/src/index.ts
index df736fb1..c6584a41 100644
--- a/packages/tendermint-rpc/src/index.ts
+++ b/packages/tendermint-rpc/src/index.ts
@@ -1,7 +1,12 @@
 export { Adaptor } from "./adaptor";
 export { adaptor33, adaptor34 } from "./adaptors";
 export { Client } from "./client";
-export { DateTime } from "./encodings";
+export {
+  DateTime,
+  ReadonlyDateWithNanoseconds,
+  fromRfc3339WithNanoseconds,
+  toRfc3339WithNanoseconds,
+} from "./dates";
 export {
   AbciInfoRequest,
   AbciQueryParams,
@@ -72,10 +77,4 @@ export {
   VoteType,
 } from "./responses";
 export { HttpClient, WebsocketClient } from "./rpcclients"; // TODO: Why do we export those outside of this package?
-export {
-  BlockIdFlag,
-  CommitSignature,
-  ReadonlyDateWithNanoseconds,
-  ValidatorEd25519Pubkey,
-  ValidatorPubkey,
-} from "./types";
+export { BlockIdFlag, CommitSignature, ValidatorEd25519Pubkey, ValidatorPubkey } from "./types";
diff --git a/packages/tendermint-rpc/src/responses.ts b/packages/tendermint-rpc/src/responses.ts
index 83e7ab65..5706726a 100644
--- a/packages/tendermint-rpc/src/responses.ts
+++ b/packages/tendermint-rpc/src/responses.ts
@@ -1,6 +1,7 @@
 import { ReadonlyDate } from "readonly-date";
 
-import { CommitSignature, ReadonlyDateWithNanoseconds, ValidatorPubkey } from "./types";
+import { ReadonlyDateWithNanoseconds } from "./dates";
+import { CommitSignature, ValidatorPubkey } from "./types";
 
 export type Response =
   | AbciInfoResponse
diff --git a/packages/tendermint-rpc/src/types.ts b/packages/tendermint-rpc/src/types.ts
index c71a10f7..1c62851c 100644
--- a/packages/tendermint-rpc/src/types.ts
+++ b/packages/tendermint-rpc/src/types.ts
@@ -1,11 +1,7 @@
 // Types in this file are exported outside of the @cosmjs/tendermint-rpc package,
 // e.g. as part of a request or response
-import { ReadonlyDate } from "readonly-date";
 
-export interface ReadonlyDateWithNanoseconds extends ReadonlyDate {
-  /* Nanoseconds after the time stored in a vanilla ReadonlyDate (millisecond granularity) */
-  readonly nanoseconds?: number;
-}
+import { ReadonlyDateWithNanoseconds } from "./dates";
 
 export interface ValidatorEd25519Pubkey {
   readonly algorithm: "ed25519";