Index: head/lib/libc/sys/thr_exit.2
===================================================================
--- head/lib/libc/sys/thr_exit.2
+++ head/lib/libc/sys/thr_exit.2
@@ -28,7 +28,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd June 1, 2016
+.Dd May 5, 2020
 .Dt THR_EXIT 2
 .Os
 .Sh NAME
@@ -88,3 +88,8 @@
 .St -p1003.1-2001
 .Xr pthread 3
 functionality.
+.Sh HISTORY
+The
+.Fn thr_exit
+system call first appeared in
+.Fx 5.2 .
Index: head/lib/libc/sys/thr_kill.2
===================================================================
--- head/lib/libc/sys/thr_kill.2
+++ head/lib/libc/sys/thr_kill.2
@@ -28,7 +28,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd June 1, 2016
+.Dd May 5, 2020
 .Dt THR_kill 2
 .Os
 .Sh NAME
@@ -131,3 +131,10 @@
 .St -p1003.1-2001
 .Xr pthread 3
 functionality.
+.Sh HISTORY
+The
+.Fn thr_kill
+and
+.Fn thr_kill2
+system calls first appeared in
+.Fx 5.2 .
Index: head/lib/libc/sys/thr_new.2
===================================================================
--- head/lib/libc/sys/thr_new.2
+++ head/lib/libc/sys/thr_new.2
@@ -28,7 +28,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd June 2, 2016
+.Dd May 5, 2020
 .Dt THR_NEW 2
 .Os
 .Sh NAME
@@ -243,3 +243,8 @@
 .St -p1003.1-2001
 .Xr pthread 3
 functionality.
+.Sh HISTORY
+The
+.Fn thr_new
+system call first appeared in
+.Fx 5.2 .
Index: head/lib/libc/sys/thr_self.2
===================================================================
--- head/lib/libc/sys/thr_self.2
+++ head/lib/libc/sys/thr_self.2
@@ -28,7 +28,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd March 3, 2020
+.Dd May 5, 2020
 .Dt THR_SELF 2
 .Os
 .Sh NAME
@@ -88,3 +88,8 @@
 .St -p1003.1-2001
 .Xr pthread 3
 functionality.
+.Sh HISTORY
+The
+.Fn thr_self
+system call first appeared in
+.Fx 5.2 .
Index: head/lib/libc/sys/thr_set_name.2
===================================================================
--- head/lib/libc/sys/thr_set_name.2
+++ head/lib/libc/sys/thr_set_name.2
@@ -28,7 +28,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd December 2, 2016
+.Dd May 5, 2020
 .Dt THR_SET_NAME 2
 .Os
 .Sh NAME
@@ -92,3 +92,8 @@
 .Fn thr_set_name
 system call is non-standard and is used by the
 .Lb libthr .
+.Sh HISTORY
+The
+.Fn thr_set_name
+system call first appeared in
+.Fx 5.2 .
Index: head/lib/libc/sys/thr_suspend.2
===================================================================
--- head/lib/libc/sys/thr_suspend.2
+++ head/lib/libc/sys/thr_suspend.2
@@ -28,7 +28,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd September 23, 2016
+.Dd May 5, 2020
 .Dt THR_SUSPEND 2
 .Os
 .Sh NAME
@@ -128,3 +128,8 @@
 The
 .Fn thr_suspend
 system call is non-standard.
+.Sh HISTORY
+The
+.Fn thr_suspend
+system call first appeared in
+.Fx 5.2 .
Index: head/lib/libc/sys/thr_wake.2
===================================================================
--- head/lib/libc/sys/thr_wake.2
+++ head/lib/libc/sys/thr_wake.2
@@ -28,7 +28,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd September 23, 2016
+.Dd May 5, 2020
 .Dt THR_WAKE 2
 .Os
 .Sh NAME
@@ -110,3 +110,8 @@
 .St -p1003.1-2001
 .Xr pthread 3
 functionality.
+.Sh HISTORY
+The
+.Fn thr_suspend
+system call first appeared in
+.Fx 5.2 .
Index: head/lib/libthr/libthr.3
===================================================================
--- head/lib/libthr/libthr.3
+++ head/lib/libthr/libthr.3
@@ -29,7 +29,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd May 17, 2016
+.Dd May 5, 2020
 .Dt LIBTHR 3
 .Os
 .Sh NAME
@@ -279,6 +279,11 @@
 .Xr pthread_create 3 ,
 .Xr signal 3 ,
 .Xr atomic 9
+.Sh HISTORY
+The
+.Nm
+library first appeared in
+.Fx 5.2 .
 .Sh AUTHORS
 .An -nosplit
 The