diff --git a/CHANGELOG.md b/CHANGELOG.md
index 391bc5dcf1..8db0550a94 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,15 @@ and this project adheres to
 
 ## [Unreleased]
 
+### Fixed
+
+- @cosmjs/encoding: Ensure RFC dates between years 0001 and 0099 are parsed
+  correctly. ([#1516])
+- @cosmjs/tendermint-rpc: Remove hacky `decodeOptionalTime()` from adaptors now
+  that `time.Time` dates are parsed correctly. ([#1516])
+
+[#1516]: https://github.com/cosmos/cosmjs/pull/1516
+
 ## [0.32.0] - 2023-11-23
 
 ### Added
diff --git a/packages/encoding/src/rfc3339.spec.ts b/packages/encoding/src/rfc3339.spec.ts
index 227f1e328e..eef19fc180 100644
--- a/packages/encoding/src/rfc3339.spec.ts
+++ b/packages/encoding/src/rfc3339.spec.ts
@@ -58,6 +58,27 @@ describe("RFC3339", () => {
     expect(fromRfc3339("2002-10-02T11:12:13.999Z")).toEqual(new Date(Date.UTC(2002, 9, 2, 11, 12, 13, 999)));
   });
 
+  it("parses dates between years 0 and 99 with and without timezones", () => {
+    expect(fromRfc3339("0001-01-01T00:00:00.000Z")).toEqual(
+      new Date(new Date(Date.UTC(1, 0, 1, 0, 0, 0, 0)).setUTCFullYear(1)),
+    );
+    expect(fromRfc3339("0000-01-01T00:00:00.000Z")).toEqual(
+      new Date(new Date(Date.UTC(0, 0, 1, 0, 0, 0, 0)).setUTCFullYear(0)),
+    );
+    expect(fromRfc3339("1999-01-01T00:00:00.000Z")).toEqual(
+      new Date(new Date(Date.UTC(1999, 0, 1, 0, 0, 0, 0)).setUTCFullYear(1999)),
+    );
+    expect(fromRfc3339("0099-01-01T00:00:00.000Z")).toEqual(
+      new Date(new Date(Date.UTC(99, 0, 1, 0, 0, 0, 0)).setUTCFullYear(99)),
+    );
+    expect(fromRfc3339("0010-01-01T00:00:00+01:00")).toEqual(
+      new Date(new Date(Date.UTC(9, 11, 31, 23, 0, 0, 0)).setUTCFullYear(9)),
+    );
+    expect(fromRfc3339("0100-01-01T00:00:00+01:00")).toEqual(
+      new Date(new Date(Date.UTC(99, 11, 31, 23, 0, 0, 0)).setUTCFullYear(99)),
+    );
+  });
+
   it("parses dates with low precision fractional seconds", () => {
     // 1 digit
     expect(fromRfc3339("2002-10-02T11:12:13.0Z")).toEqual(new Date(Date.UTC(2002, 9, 2, 11, 12, 13, 0)));
diff --git a/packages/encoding/src/rfc3339.ts b/packages/encoding/src/rfc3339.ts
index a385ca1c0a..21a3050246 100644
--- a/packages/encoding/src/rfc3339.ts
+++ b/packages/encoding/src/rfc3339.ts
@@ -40,8 +40,11 @@ export function fromRfc3339(str: string): Date {
 
   const tzOffset = tzOffsetSign * (tzOffsetHours * 60 + tzOffsetMinutes) * 60; // seconds
 
-  const timestamp = Date.UTC(year, month - 1, day, hour, minute, second, milliSeconds) - tzOffset * 1000;
-  return new Date(timestamp);
+  const date = new Date();
+  date.setUTCFullYear(year, month - 1, day);
+  date.setUTCHours(hour, minute, second, milliSeconds);
+
+  return new Date(date.getTime() - tzOffset * 1000);
 }
 
 export function toRfc3339(date: Date | ReadonlyDate): string {
diff --git a/packages/tendermint-rpc/src/comet38/adaptor/responses.ts b/packages/tendermint-rpc/src/comet38/adaptor/responses.ts
index 6bec2343b7..d540481cbd 100644
--- a/packages/tendermint-rpc/src/comet38/adaptor/responses.ts
+++ b/packages/tendermint-rpc/src/comet38/adaptor/responses.ts
@@ -3,7 +3,7 @@ import { fromBase64, fromHex } from "@cosmjs/encoding";
 import { JsonRpcSuccessResponse } from "@cosmjs/json-rpc";
 import { assert } from "@cosmjs/utils";
 
-import { DateWithNanoseconds, fromRfc3339WithNanoseconds } from "../../dates";
+import { fromRfc3339WithNanoseconds } from "../../dates";
 import { apiToBigInt, apiToSmallInt } from "../../inthelpers";
 import { SubscriptionEvent } from "../../rpcclients";
 import { BlockIdFlag, CommitSignature, ValidatorPubkey } from "../../types";
@@ -467,22 +467,11 @@ type RpcSignature = {
   readonly signature: string | null;
 };
 
-/**
- * In some cases a timestamp is optional and set to the value 0 in Go.
- * This can lead to strings like "0001-01-01T00:00:00Z" (see https://github.com/cosmos/cosmjs/issues/704#issuecomment-797122415).
- * This decoder tries to clean up such encoding from the API and turn them
- * into undefined values.
- */
-function decodeOptionalTime(timestamp: string): DateWithNanoseconds | undefined {
-  const nonZeroTime = timestamp && !timestamp.startsWith("0001-01-01");
-  return nonZeroTime ? fromRfc3339WithNanoseconds(timestamp) : undefined;
-}
-
 function decodeCommitSignature(data: RpcSignature): CommitSignature {
   return {
     blockIdFlag: decodeBlockIdFlag(data.block_id_flag),
     validatorAddress: data.validator_address ? fromHex(data.validator_address) : undefined,
-    timestamp: decodeOptionalTime(data.timestamp),
+    timestamp: data.timestamp ? fromRfc3339WithNanoseconds(data.timestamp) : undefined,
     signature: data.signature ? fromBase64(data.signature) : undefined,
   };
 }
diff --git a/packages/tendermint-rpc/src/tendermint34/adaptor/responses.ts b/packages/tendermint-rpc/src/tendermint34/adaptor/responses.ts
index b3546dd914..48acab2aab 100644
--- a/packages/tendermint-rpc/src/tendermint34/adaptor/responses.ts
+++ b/packages/tendermint-rpc/src/tendermint34/adaptor/responses.ts
@@ -3,7 +3,7 @@ import { fromBase64, fromHex } from "@cosmjs/encoding";
 import { JsonRpcSuccessResponse } from "@cosmjs/json-rpc";
 import { assert } from "@cosmjs/utils";
 
-import { DateWithNanoseconds, fromRfc3339WithNanoseconds } from "../../dates";
+import { fromRfc3339WithNanoseconds } from "../../dates";
 import { apiToBigInt, apiToSmallInt } from "../../inthelpers";
 import { SubscriptionEvent } from "../../rpcclients";
 import { BlockIdFlag, CommitSignature, ValidatorPubkey } from "../../types";
@@ -464,22 +464,11 @@ type RpcSignature = {
   readonly signature: string | null;
 };
 
-/**
- * In some cases a timestamp is optional and set to the value 0 in Go.
- * This can lead to strings like "0001-01-01T00:00:00Z" (see https://github.com/cosmos/cosmjs/issues/704#issuecomment-797122415).
- * This decoder tries to clean up such encoding from the API and turn them
- * into undefined values.
- */
-function decodeOptionalTime(timestamp: string): DateWithNanoseconds | undefined {
-  const nonZeroTime = timestamp && !timestamp.startsWith("0001-01-01");
-  return nonZeroTime ? fromRfc3339WithNanoseconds(timestamp) : undefined;
-}
-
 function decodeCommitSignature(data: RpcSignature): CommitSignature {
   return {
     blockIdFlag: decodeBlockIdFlag(data.block_id_flag),
     validatorAddress: data.validator_address ? fromHex(data.validator_address) : undefined,
-    timestamp: decodeOptionalTime(data.timestamp),
+    timestamp: data.timestamp ? fromRfc3339WithNanoseconds(data.timestamp) : undefined,
     signature: data.signature ? fromBase64(data.signature) : undefined,
   };
 }
diff --git a/packages/tendermint-rpc/src/tendermint37/adaptor/responses.ts b/packages/tendermint-rpc/src/tendermint37/adaptor/responses.ts
index f0614ed49f..70d13caf26 100644
--- a/packages/tendermint-rpc/src/tendermint37/adaptor/responses.ts
+++ b/packages/tendermint-rpc/src/tendermint37/adaptor/responses.ts
@@ -3,7 +3,7 @@ import { fromBase64, fromHex } from "@cosmjs/encoding";
 import { JsonRpcSuccessResponse } from "@cosmjs/json-rpc";
 import { assert } from "@cosmjs/utils";
 
-import { DateWithNanoseconds, fromRfc3339WithNanoseconds } from "../../dates";
+import { fromRfc3339WithNanoseconds } from "../../dates";
 import { apiToBigInt, apiToSmallInt } from "../../inthelpers";
 import { SubscriptionEvent } from "../../rpcclients";
 import { BlockIdFlag, CommitSignature, ValidatorPubkey } from "../../types";
@@ -465,22 +465,11 @@ type RpcSignature = {
   readonly signature: string | null;
 };
 
-/**
- * In some cases a timestamp is optional and set to the value 0 in Go.
- * This can lead to strings like "0001-01-01T00:00:00Z" (see https://github.com/cosmos/cosmjs/issues/704#issuecomment-797122415).
- * This decoder tries to clean up such encoding from the API and turn them
- * into undefined values.
- */
-function decodeOptionalTime(timestamp: string): DateWithNanoseconds | undefined {
-  const nonZeroTime = timestamp && !timestamp.startsWith("0001-01-01");
-  return nonZeroTime ? fromRfc3339WithNanoseconds(timestamp) : undefined;
-}
-
 function decodeCommitSignature(data: RpcSignature): CommitSignature {
   return {
     blockIdFlag: decodeBlockIdFlag(data.block_id_flag),
     validatorAddress: data.validator_address ? fromHex(data.validator_address) : undefined,
-    timestamp: decodeOptionalTime(data.timestamp),
+    timestamp: data.timestamp ? fromRfc3339WithNanoseconds(data.timestamp) : undefined,
     signature: data.signature ? fromBase64(data.signature) : undefined,
   };
 }