diff --git a/config.h b/config.h
index 935b4dd1..e1b27c12 100644
--- a/config.h
+++ b/config.h
@@ -3,7 +3,7 @@
 /// \file config.h
 /// \brief Library configuration file
 /// \details <tt>config.h</tt> was split into components in May 2019 to better
-///  integrate with Autoconf and its feature tests. The splitting occured so
+///  integrate with Autoconf and its feature tests. The splitting occurred so
 ///  users could continue to include <tt>config.h</tt> while allowing Autoconf
 ///  to write new <tt>config_asm.h</tt> and new <tt>config_cxx.h</tt> using
 ///  its feature tests.
diff --git a/config_align.h b/config_align.h
index 0f2d0b34..97e85d82 100644
--- a/config_align.h
+++ b/config_align.h
@@ -5,7 +5,7 @@
 /// \file config_align.h
 /// \brief Library configuration file
 /// \details <tt>config.h</tt> was split into components in May 2019 to better
-///  integrate with Autoconf and its feature tests. The splitting occured so
+///  integrate with Autoconf and its feature tests. The splitting occurred so
 ///  users could continue to include <tt>config.h</tt> while allowing Autoconf
 ///  to write new <tt>config_asm.h</tt> and new <tt>config_cxx.h</tt> using
 ///  its feature tests.
diff --git a/config_asm.h b/config_asm.h
index 6d7e4802..c94326ab 100644
--- a/config_asm.h
+++ b/config_asm.h
@@ -5,7 +5,7 @@
 /// \file config_asm.h
 /// \brief Library configuration file
 /// \details <tt>config.h</tt> was split into components in May 2019 to better
-///  integrate with Autoconf and its feature tests. The splitting occured so
+///  integrate with Autoconf and its feature tests. The splitting occurred so
 ///  users could continue to include <tt>config.h</tt> while allowing Autoconf
 ///  to write new <tt>config_asm.h</tt> and new <tt>config_cxx.h</tt> using
 ///  its feature tests.
diff --git a/config_cpu.h b/config_cpu.h
index 6f5d400a..2d593977 100644
--- a/config_cpu.h
+++ b/config_cpu.h
@@ -5,7 +5,7 @@
 /// \file config_cpu.h
 /// \brief Library configuration file
 /// \details <tt>config.h</tt> was split into components in May 2019 to better
-///  integrate with Autoconf and its feature tests. The splitting occured so
+///  integrate with Autoconf and its feature tests. The splitting occurred so
 ///  users could continue to include <tt>config.h</tt> while allowing Autoconf
 ///  to write new <tt>config_asm.h</tt> and new <tt>config_cxx.h</tt> using
 ///  its feature tests.
diff --git a/config_cxx.h b/config_cxx.h
index 23f7640c..bcf1fc9c 100644
--- a/config_cxx.h
+++ b/config_cxx.h
@@ -5,7 +5,7 @@
 /// \file config_cxx.h
 /// \brief Library configuration file
 /// \details <tt>config.h</tt> was split into components in May 2019 to better
-///  integrate with Autoconf and its feature tests. The splitting occured so
+///  integrate with Autoconf and its feature tests. The splitting occurred so
 ///  users could continue to include <tt>config.h</tt> while allowing Autoconf
 ///  to write new <tt>config_asm.h</tt> and new <tt>config_cxx.h</tt> using
 ///  its feature tests.
diff --git a/config_dll.h b/config_dll.h
index 2fcd9987..b33ad757 100644
--- a/config_dll.h
+++ b/config_dll.h
@@ -5,7 +5,7 @@
 /// \file config_dll.h
 /// \brief Library configuration file
 /// \details <tt>config.h</tt> was split into components in May 2019 to better
-///  integrate with Autoconf and its feature tests. The splitting occured so
+///  integrate with Autoconf and its feature tests. The splitting occurred so
 ///  users could continue to include <tt>config.h</tt> while allowing Autoconf
 ///  to write new <tt>config_asm.h</tt> and new <tt>config_cxx.h</tt> using
 ///  its feature tests.
diff --git a/config_int.h b/config_int.h
index 49568bc4..74ddfed9 100644
--- a/config_int.h
+++ b/config_int.h
@@ -5,7 +5,7 @@
 /// \file config_int.h
 /// \brief Library configuration file
 /// \details <tt>config.h</tt> was split into components in May 2019 to better
-///  integrate with Autoconf and its feature tests. The splitting occured so
+///  integrate with Autoconf and its feature tests. The splitting occurred so
 ///  users could continue to include <tt>config.h</tt> while allowing Autoconf
 ///  to write new <tt>config_asm.h</tt> and new <tt>config_cxx.h</tt> using
 ///  its feature tests.
diff --git a/config_misc.h b/config_misc.h
index 2bdc1014..6530318c 100644
--- a/config_misc.h
+++ b/config_misc.h
@@ -5,7 +5,7 @@
 /// \file config_misc.h
 /// \brief Library configuration file
 /// \details <tt>config.h</tt> was split into components in May 2019 to better
-///  integrate with Autoconf and its feature tests. The splitting occured so
+///  integrate with Autoconf and its feature tests. The splitting occurred so
 ///  users could continue to include <tt>config.h</tt> while allowing Autoconf
 ///  to write new <tt>config_asm.h</tt> and new <tt>config_cxx.h</tt> using
 ///  its feature tests.
diff --git a/config_ns.h b/config_ns.h
index f109809a..2bbb5823 100644
--- a/config_ns.h
+++ b/config_ns.h
@@ -5,7 +5,7 @@
 /// \file config_ns.h
 /// \brief Library configuration file
 /// \details <tt>config.h</tt> was split into components in May 2019 to better
-///  integrate with Autoconf and its feature tests. The splitting occured so
+///  integrate with Autoconf and its feature tests. The splitting occurred so
 ///  users could continue to include <tt>config.h</tt> while allowing Autoconf
 ///  to write new <tt>config_asm.h</tt> and new <tt>config_cxx.h</tt> using
 ///  its feature tests.
diff --git a/config_os.h b/config_os.h
index 1594e0ee..32655488 100644
--- a/config_os.h
+++ b/config_os.h
@@ -5,7 +5,7 @@
 /// \file config_os.h
 /// \brief Library configuration file
 /// \details <tt>config.h</tt> was split into components in May 2019 to better
-///  integrate with Autoconf and its feature tests. The splitting occured so
+///  integrate with Autoconf and its feature tests. The splitting occurred so
 ///  users could continue to include <tt>config.h</tt> while allowing Autoconf
 ///  to write new <tt>config_asm.h</tt> and new <tt>config_cxx.h</tt> using
 ///  its feature tests.
diff --git a/config_ver.h b/config_ver.h
index 84f52723..9bf5b387 100644
--- a/config_ver.h
+++ b/config_ver.h
@@ -5,7 +5,7 @@
 /// \file config_ver.h
 /// \brief Library configuration file
 /// \details <tt>config.h</tt> was split into components in May 2019 to better
-///  integrate with Autoconf and its feature tests. The splitting occured so
+///  integrate with Autoconf and its feature tests. The splitting occurred so
 ///  users could continue to include <tt>config.h</tt> while allowing Autoconf
 ///  to write new <tt>config_asm.h</tt> and new <tt>config_cxx.h</tt> using
 ///  its feature tests.
diff --git a/regtest1.cpp b/regtest1.cpp
index caefc2c9..dc9b6324 100644
--- a/regtest1.cpp
+++ b/regtest1.cpp
@@ -1,6 +1,6 @@
 // regtest1.cpp - originally written and placed in the public domain by Wei Dai
 //                regtest.cpp split into 3 files due to OOM kills by JW
-//                in April 2017. A second split occured in July 2018.
+//                in April 2017. A second split occurred in July 2018.
 
 #define CRYPTOPP_ENABLE_NAMESPACE_WEAK 1
 
diff --git a/regtest2.cpp b/regtest2.cpp
index e14036fa..e379432d 100644
--- a/regtest2.cpp
+++ b/regtest2.cpp
@@ -1,6 +1,6 @@
 // regtest2.cpp - originally written and placed in the public domain by Wei Dai
 //                regtest.cpp split into 3 files due to OOM kills by JW
-//                in April 2017. A second split occured in July 2018.
+//                in April 2017. A second split occurred in July 2018.
 
 #define CRYPTOPP_ENABLE_NAMESPACE_WEAK 1
 
diff --git a/regtest3.cpp b/regtest3.cpp
index 517b8acd..370756a6 100644
--- a/regtest3.cpp
+++ b/regtest3.cpp
@@ -1,6 +1,6 @@
 // regtest3.cpp - originally written and placed in the public domain by Wei Dai
 //                regtest.cpp split into 3 files due to OOM kills by JW
-//                in April 2017. A second split occured in July 2018.
+//                in April 2017. A second split occurred in July 2018.
 
 #define CRYPTOPP_ENABLE_NAMESPACE_WEAK 1
 
diff --git a/regtest4.cpp b/regtest4.cpp
index 87c89477..f4532083 100644
--- a/regtest4.cpp
+++ b/regtest4.cpp
@@ -1,6 +1,6 @@
 // regtest4.cpp - originally written and placed in the public domain by Wei Dai
 //                regtest.cpp split into 3 files due to OOM kills by JW
-//                in April 2017. A second split occured in July 2018.
+//                in April 2017. A second split occurred in July 2018.
 
 #define CRYPTOPP_ENABLE_NAMESPACE_WEAK 1