diff --git a/Lib/calendar.py b/Lib/calendar.py
index 07594f3a8..7550d52c0 100644
--- a/Lib/calendar.py
+++ b/Lib/calendar.py
@@ -111,8 +111,9 @@ def leapdays(y1, y2):
 
 
 def weekday(year, month, day):
-    """Return weekday (0-6 ~ Mon-Sun) for year (1970-...), month (1-12),
-       day (1-31)."""
+    """Return weekday (0-6 ~ Mon-Sun) for year, month (1-12), day (1-31)."""
+    if not datetime.MINYEAR <= year <= datetime.MAXYEAR:
+        year = 2000 + year % 400
     return datetime.date(year, month, day).weekday()
 
 
@@ -126,6 +127,24 @@ def monthrange(year, month):
     return day1, ndays
 
 
+def _monthlen(year, month):
+    return mdays[month] + (month == February and isleap(year))
+
+
+def _prevmonth(year, month):
+    if month == 1:
+        return year-1, 12
+    else:
+        return year, month-1
+
+
+def _nextmonth(year, month):
+    if month == 12:
+        return year+1, 1
+    else:
+        return year, month+1
+
+
 class Calendar(object):
     """
     Base calendar class. This class doesn't do any formatting. It simply
@@ -157,28 +176,8 @@ class Calendar(object):
         values and will always iterate through complete weeks, so it will yield
         dates outside the specified month.
         """
-        date = datetime.date(year, month, 1)
-        # Go back to the beginning of the week
-        days = (date.weekday() - self.firstweekday) % 7
-        date -= datetime.timedelta(days=days)
-        oneday = datetime.timedelta(days=1)
-        while True:
-            yield date
-            try:
-                date += oneday
-            except OverflowError:
-                # Adding one day could fail after datetime.MAXYEAR
-                break
-            if date.month != month and date.weekday() == self.firstweekday:
-                break
-
-    def itermonthdays2(self, year, month):
-        """
-        Like itermonthdates(), but will yield (day number, weekday number)
-        tuples. For days outside the specified month the day number is 0.
-        """
-        for i, d in enumerate(self.itermonthdays(year, month), self.firstweekday):
-            yield d, i % 7
+        for y, m, d in self.itermonthdays3(year, month):
+            yield datetime.date(y, m, d)
 
     def itermonthdays(self, year, month):
         """
@@ -192,6 +191,40 @@ class Calendar(object):
         days_after = (self.firstweekday - day1 - ndays) % 7
         yield from repeat(0, days_after)
 
+    def itermonthdays2(self, year, month):
+        """
+        Like itermonthdates(), but will yield (day number, weekday number)
+        tuples. For days outside the specified month the day number is 0.
+        """
+        for i, d in enumerate(self.itermonthdays(year, month), self.firstweekday):
+            yield d, i % 7
+
+    def itermonthdays3(self, year, month):
+        """
+        Like itermonthdates(), but will yield (year, month, day) tuples.  Can be
+        used for dates outside of datetime.date range.
+        """
+        day1, ndays = monthrange(year, month)
+        days_before = (day1 - self.firstweekday) % 7
+        days_after = (self.firstweekday - day1 - ndays) % 7
+        y, m = _prevmonth(year, month)
+        end = _monthlen(y, m) + 1
+        for d in range(end-days_before, end):
+            yield y, m, d
+        for d in range(1, ndays + 1):
+            yield year, month, d
+        y, m = _nextmonth(year, month)
+        for d in range(1, days_after + 1):
+            yield y, m, d
+
+    def itermonthdays4(self, year, month):
+        """
+        Like itermonthdates(), but will yield (year, month, day, day_of_week) tuples.
+        Can be used for dates outside of datetime.date range.
+        """
+        for i, (y, m, d) in enumerate(self.itermonthdays3(year, month)):
+            yield y, m, d, (self.firstweekday + i) % 7
+
     def monthdatescalendar(self, year, month):
         """
         Return a matrix (list of lists) representing a month's calendar.
@@ -267,7 +300,7 @@ class TextCalendar(Calendar):
         """
         Print a single week (no newline).
         """
-        print(self.formatweek(theweek, width), end=' ')
+        print(self.formatweek(theweek, width), end='')
 
     def formatday(self, day, weekday, width):
         """
@@ -371,7 +404,7 @@ class TextCalendar(Calendar):
 
     def pryear(self, theyear, w=0, l=0, c=6, m=3):
         """Print a year's calendar."""
-        print(self.formatyear(theyear, w, l, c, m))
+        print(self.formatyear(theyear, w, l, c, m), end='')
 
 
 class HTMLCalendar(Calendar):
@@ -382,12 +415,31 @@ class HTMLCalendar(Calendar):
     # CSS classes for the day <td>s
     cssclasses = ["mon", "tue", "wed", "thu", "fri", "sat", "sun"]
 
+    # CSS classes for the day <th>s
+    cssclasses_weekday_head = cssclasses
+
+    # CSS class for the days before and after current month
+    cssclass_noday = "noday"
+
+    # CSS class for the month's head
+    cssclass_month_head = "month"
+
+    # CSS class for the month
+    cssclass_month = "month"
+
+    # CSS class for the year's table head
+    cssclass_year_head = "year"
+
+    # CSS class for the whole year table
+    cssclass_year = "year"
+
     def formatday(self, day, weekday):
         """
         Return a day as a table cell.
         """
         if day == 0:
-            return '<td class="noday">&nbsp;</td>' # day outside month
+            # day outside month
+            return '<td class="%s">&nbsp;</td>' % self.cssclass_noday
         else:
             return '<td class="%s">%d</td>' % (self.cssclasses[weekday], day)
 
@@ -402,7 +454,8 @@ class HTMLCalendar(Calendar):
         """
         Return a weekday name as a table header.
         """
-        return '<th class="%s">%s</th>' % (self.cssclasses[day], day_abbr[day])
+        return '<th class="%s">%s</th>' % (
+            self.cssclasses_weekday_head[day], day_abbr[day])
 
     def formatweekheader(self):
         """
@@ -419,7 +472,8 @@ class HTMLCalendar(Calendar):
             s = '%s %s' % (month_name[themonth], theyear)
         else:
             s = '%s' % month_name[themonth]
-        return '<tr><th colspan="7" class="month">%s</th></tr>' % s
+        return '<tr><th colspan="7" class="%s">%s</th></tr>' % (
+            self.cssclass_month_head, s)
 
     def formatmonth(self, theyear, themonth, withyear=True):
         """
@@ -427,7 +481,8 @@ class HTMLCalendar(Calendar):
         """
         v = []
         a = v.append
-        a('<table border="0" cellpadding="0" cellspacing="0" class="month">')
+        a('<table border="0" cellpadding="0" cellspacing="0" class="%s">' % (
+            self.cssclass_month))
         a('\n')
         a(self.formatmonthname(theyear, themonth, withyear=withyear))
         a('\n')
@@ -447,9 +502,11 @@ class HTMLCalendar(Calendar):
         v = []
         a = v.append
         width = max(width, 1)
-        a('<table border="0" cellpadding="0" cellspacing="0" class="year">')
+        a('<table border="0" cellpadding="0" cellspacing="0" class="%s">' %
+          self.cssclass_year)
         a('\n')
-        a('<tr><th colspan="%d" class="year">%s</th></tr>' % (width, theyear))
+        a('<tr><th colspan="%d" class="%s">%s</th></tr>' % (
+            width, self.cssclass_year_head, theyear))
         for i in range(January, January+12, width):
             # months in this row
             months = range(i, min(i+width, 13))