diff --git a/src/Config.cpp b/src/Config.cpp
index f726176e0..f6617f766 100644
--- a/src/Config.cpp
+++ b/src/Config.cpp
@@ -33,7 +33,7 @@
 #include <inttypes.h>
 #include <unistd.h>
 #include <stdlib.h>
-#include <Date.h>
+#include <ISO8601.h>
 #include <FS.h>
 #include <Timer.h>
 #include <JSON.h>
@@ -574,7 +574,7 @@ void Config::createDefaultRC (const std::string& rc, const std::string& data)
   auto loc = _defaults.find ("data.location=~/.task");
   //                                      loc+0^          +14^   +21^
 
-  Date now;
+  ISO8601d now;
   std::stringstream contents;
   contents << "# [Created by "
            << PACKAGE_STRING
diff --git a/src/columns/ColDate.cpp b/src/columns/ColDate.cpp
index a35a6d386..6bc4e87c7 100644
--- a/src/columns/ColDate.cpp
+++ b/src/columns/ColDate.cpp
@@ -89,7 +89,7 @@ void ColumnDate::measure (Task& task, unsigned int& minimum, unsigned int& maxim
       if (format == "")
         format = context.config.get ("dateformat");
 
-      minimum = maximum = Date::length (format);
+      minimum = maximum = ISO8601d::length (format);
     }
     else if (_style == "countdown")
     {
diff --git a/src/columns/ColDescription.cpp b/src/columns/ColDescription.cpp
index abf376db9..4d4304e47 100644
--- a/src/columns/ColDescription.cpp
+++ b/src/columns/ColDescription.cpp
@@ -27,7 +27,7 @@
 #include <cmake.h>
 #include <stdlib.h>
 #include <Context.h>
-#include <Date.h>
+#include <ISO8601.h>
 #include <ColDescription.h>
 #include <text.h>
 #include <utf8.h>
@@ -55,7 +55,7 @@ ColumnDescription::ColumnDescription ()
   if (_dateformat == "")
     _dateformat = context.config.get ("dateformat");
 
-  std::string t  = Date ().toString (_dateformat);
+  std::string t  = ISO8601d ().toString (_dateformat);
   std::string d  = STRING_COLUMN_EXAMPLES_DESC;
   std::string a1 = STRING_COLUMN_EXAMPLES_ANNO1;
   std::string a2 = STRING_COLUMN_EXAMPLES_ANNO2;
@@ -102,7 +102,7 @@ void ColumnDescription::measure (Task& task, unsigned int& minimum, unsigned int
 
     if (task.annotation_count)
     {
-      unsigned int min_anno = _indent + Date::length (_dateformat);
+      unsigned int min_anno = _indent + ISO8601d::length (_dateformat);
       if (min_anno > minimum)
         minimum = min_anno;
 
@@ -132,7 +132,7 @@ void ColumnDescription::measure (Task& task, unsigned int& minimum, unsigned int
 
     if (task.annotation_count)
     {
-      auto min_anno = Date::length (_dateformat);
+      auto min_anno = ISO8601d::length (_dateformat);
       std::map <std::string, std::string> annos;
       task.getAnnotations (annos);
       for (auto& i : annos)
@@ -187,7 +187,7 @@ void ColumnDescription::render (
     {
       for (auto& i : annos)
       {
-        Date dt (strtol (i.first.substr (11).c_str (), NULL, 10));
+        ISO8601d dt (strtol (i.first.substr (11).c_str (), NULL, 10));
         description += "\n" + std::string (_indent, ' ') + dt.toString (_dateformat) + " " + i.second;
       }
     }
@@ -218,7 +218,7 @@ void ColumnDescription::render (
     {
       for (auto& i : annos)
       {
-        Date dt (atoi (i.first.substr (11).c_str ()));
+        ISO8601d dt (strtol (i.first.substr (11).c_str (), NULL, 10));
         description += " " + dt.toString (_dateformat) + " " + i.second;
       }
     }
diff --git a/src/commands/CmdBurndown.cpp b/src/commands/CmdBurndown.cpp
index 9ea606b5c..924b487b5 100644
--- a/src/commands/CmdBurndown.cpp
+++ b/src/commands/CmdBurndown.cpp
@@ -744,7 +744,7 @@ void Chart::generateBars ()
     {
     case 'D': // month/day
       {
-        std::string month = Date::monthName (cursor.month ());
+        std::string month = ISO8601d::monthName (cursor.month ());
         bar._major_label = month.substr (0, 3);
 
         sprintf (str, "%02d", cursor.day ());
diff --git a/src/commands/CmdHistory.cpp b/src/commands/CmdHistory.cpp
index dc81af131..4280d6387 100644
--- a/src/commands/CmdHistory.cpp
+++ b/src/commands/CmdHistory.cpp
@@ -478,7 +478,7 @@ int CmdGHistoryMonthly::execute (std::string& output)
         view.set (row, 0, y);
         priorYear = y;
       }
-      view.set (row, 1, Date::monthName(m));
+      view.set (row, 1, ISO8601d::monthName(m));
 
       unsigned int addedBar     = (widthOfBar *     addedGroup[i.first]) / maxLine;
       unsigned int completedBar = (widthOfBar * completedGroup[i.first]) / maxLine;
diff --git a/src/commands/CmdTimesheet.cpp b/src/commands/CmdTimesheet.cpp
index 775213f69..4afa20393 100644
--- a/src/commands/CmdTimesheet.cpp
+++ b/src/commands/CmdTimesheet.cpp
@@ -30,6 +30,7 @@
 #include <Context.h>
 #include <Filter.h>
 #include <ViewText.h>
+#include <ISO8601.h>
 #include <Date.h>
 #include <main.h>
 #include <i18n.h>
@@ -64,7 +65,7 @@ int CmdTimesheet::execute (std::string& output)
   std::vector <Task> all = context.tdb2.all_tasks ();
 
   // What day of the week does the user consider the first?
-  int weekStart = Date::dayOfWeek (context.config.get ("weekstart"));
+  int weekStart = ISO8601d::dayOfWeek (context.config.get ("weekstart"));
   if (weekStart != 0 && weekStart != 1)
     throw std::string (STRING_DATE_BAD_WEEKSTART);