diff --git a/CHANGELOG.md b/CHANGELOG.md
index 14d3cebc..f25d6bc4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 
 ## unreleased
 
+- Year `0000` may be disallowed in Date-Times and Dates.
 - Clarify Unicode and UTF-8 references.
 - Relax comment parsing; most control characters are again permitted.
 - Allow newline after key/values in inline tables.
diff --git a/toml.md b/toml.md
index 8862f0ea..09638bb4 100644
--- a/toml.md
+++ b/toml.md
@@ -569,14 +569,22 @@ time with a space character (as permitted by RFC 3339 section 5.6).
 odt4 = 1979-05-27 07:32:00Z
 ```
 
-One exception to RFC 3339 is permitted: seconds may be omitted, in which case
-`:00` will be assumed. The offset immediately follows the minutes.
+Contrary to RFC 3339, seconds may be omitted, in which case `:00` will be assumed. The
+offset immediately follows the minutes.
 
 ```toml
 odt5 = 1979-05-27 07:32Z
 odt6 = 1979-05-27 07:32-07:00
 ```
 
+Date-times in the year `0000` may throw errors for technical reasons. Although some
+platforms may recognize year-zero date-times, for the sake of interoperability, avoid
+using year-zero date-times in TOML documents.
+
+```toml
+odt_year1 = 0001-01-01 00:00:00Z  # NOTE: Earliest date-time guaranteed to be valid.
+```
+
 Millisecond precision is required. Further precision of fractional seconds is
 implementation-specific. If the value contains greater precision than the
 implementation can support, the additional precision must be truncated, not
@@ -601,6 +609,9 @@ Seconds may be omitted, in which case `:00` will be assumed.
 ldt3 = 1979-05-27T07:32
 ```
 
+Date-times in the year `0000` may throw errors for technical reasons. Avoid them in TOML
+documents.
+
 Millisecond precision is required. Further precision of fractional seconds is
 implementation-specific. If the value contains greater precision than the
 implementation can support, the additional precision must be truncated, not
@@ -616,6 +627,9 @@ represent that entire day without any relation to an offset or timezone.
 ld1 = 1979-05-27
 ```
 
+Dates in the year `0000` may throw errors for technical reasons. Avoid them in TOML
+documents.
+
 ## Local Time
 
 If you include only the time portion of an