diff --git a/sys/man/1/io b/sys/man/1/io
index 5dea3ee49..e672619b3 100644
--- a/sys/man/1/io
+++ b/sys/man/1/io
@@ -46,3 +46,6 @@ Access embedded controller space.
 .SH SEE ALSO
 .IR seg (1),
 .IR arch (3)
+.SH HISTORY
+.I Io
+first appeared in 9front (April, 2011).
diff --git a/sys/man/1/seg b/sys/man/1/seg
index 3fd87f2e2..1e17b6640 100644
--- a/sys/man/1/seg
+++ b/sys/man/1/seg
@@ -49,3 +49,6 @@ and
 .I offset
 parameters is performed whatsoever.
 Odd values may cause the front to fall off.
+.SH HISTORY
+.I Seg
+first appeared in 9front (April, 2011).