diff --git a/gramps/gen/lib/date.py b/gramps/gen/lib/date.py
index 1db1d62de..e61caba1d 100644
--- a/gramps/gen/lib/date.py
+++ b/gramps/gen/lib/date.py
@@ -1869,3 +1869,10 @@ def lookup_calendar(calendar):
             return pos
     raise AttributeError("invalid calendar: '%s'" % calendar)
 
+def gregorian(date):
+    """Convert given date to gregorian. Doesn't modify the original object."""
+    if date.get_calendar() != Date.CAL_GREGORIAN:
+        date = Date(date)
+        date.convert_calendar(Date.CAL_GREGORIAN)
+    return date
+
diff --git a/gramps/plugins/drawreport/calendarreport.py b/gramps/plugins/drawreport/calendarreport.py
index 53ddabd9c..fe774e867 100644
--- a/gramps/plugins/drawreport/calendarreport.py
+++ b/gramps/plugins/drawreport/calendarreport.py
@@ -54,6 +54,7 @@ from gramps.gen.plug.report import stdoptions
 from gramps.gen.utils.alive import probably_alive
 from gramps.gen.datehandler import displayer as _dd, long_days
 from gramps.gen.lib import Date, EventRoleType, EventType, Name, NameType, Person, Surname
+from gramps.gen.lib.date import gregorian
 
 import gramps.plugins.lib.libholiday as libholiday
 from gramps.plugins.lib.libholiday import g2iso
@@ -285,6 +286,8 @@ class Calendar(Report):
                     birth_date = birth_event.get_date_object()
 
                 if (self.birthdays and birth_date is not None and birth_date.is_valid()):
+                    birth_date = gregorian(birth_date)
+
                     year = birth_date.get_year()
                     month = birth_date.get_month()
                     day = birth_date.get_day()
@@ -366,6 +369,8 @@ class Calendar(Report):
                                         event_obj = event.get_date_object()
 
                                         if event_obj.is_valid():
+                                            event_obj = gregorian(event_obj)
+
                                             year = event_obj.get_year()
                                             month = event_obj.get_month()
                                             day = event_obj.get_day()
diff --git a/gramps/plugins/drawreport/statisticschart.py b/gramps/plugins/drawreport/statisticschart.py
index 1625a50e5..6c5ddf8b0 100644
--- a/gramps/plugins/drawreport/statisticschart.py
+++ b/gramps/plugins/drawreport/statisticschart.py
@@ -46,7 +46,7 @@ from gramps.gen.const import GRAMPS_LOCALE as glocale
 _ = glocale.translation.sgettext
 # Person and relation types
 from gramps.gen.lib import Person, FamilyRelType, EventType, EventRoleType
-from gramps.gen.lib.date import Date
+from gramps.gen.lib.date import Date, gregorian
 # gender and report type names
 from gramps.gen.plug.docgen import (FontStyle, ParagraphStyle, GraphicsStyle,
                                     FONT_SANS_SERIF, FONT_SERIF,
@@ -669,6 +669,8 @@ class Extract(object):
             if birth:
                 birthdate = birth.get_date_object()
                 if birthdate.get_year_valid():
+                    birthdate = gregorian(birthdate)
+
                     year = birthdate.get_year()
                     if not (year >= year_from and year <= year_to):
                         continue
@@ -677,8 +679,11 @@ class Extract(object):
                     death = self.get_death(person)
                     if death:
                         deathdate = death.get_date_object()
-                        if deathdate.get_year_valid() and deathdate.get_year() < year_from:
-                            continue
+                        if deathdate.get_year_valid():
+                            deathdate = gregorian(deathdate)
+
+                            if deathdate.get_year() < year_from:
+                                continue
                         if not no_years:
                             # do not accept people who are not known to be in range
                             continue
diff --git a/gramps/plugins/textreport/birthdayreport.py b/gramps/plugins/textreport/birthdayreport.py
index 365e28f15..32451a573 100644
--- a/gramps/plugins/textreport/birthdayreport.py
+++ b/gramps/plugins/textreport/birthdayreport.py
@@ -42,6 +42,7 @@ from gramps.gen.const import URL_HOMEPAGE
 from gramps.gen.display.name import displayer as global_name_display
 from gramps.gen.errors import ReportError
 from gramps.gen.lib import NameType, EventType, Name, Date, Person, Surname
+from gramps.gen.lib.date import gregorian
 from gramps.gen.relationship import get_relationship_calculator
 from gramps.gen.plug.docgen import (FontStyle, ParagraphStyle, GraphicsStyle,
                                     FONT_SERIF, PARA_ALIGN_RIGHT,
@@ -277,6 +278,8 @@ class BirthdayReport(Report):
                     birth_date = birth_event.get_date_object()
 
                 if (self.birthdays and birth_date is not None and birth_date.is_valid()):
+                    birth_date = gregorian(birth_date)
+
                     year = birth_date.get_year()
                     month = birth_date.get_month()
                     day = birth_date.get_day()
@@ -364,6 +367,8 @@ class BirthdayReport(Report):
                                     for event_ref in fam.get_event_ref_list():
                                         event = self.database.get_event_from_handle(event_ref.ref)
                                         event_obj = event.get_date_object()
+                                        if event_obj is not Date.EMPTY and event_obj.is_valid():
+                                            event_obj = gregorian(event_obj)
                                         year = event_obj.get_year()
                                         month = event_obj.get_month()
                                         day = event_obj.get_day()
diff --git a/gramps/plugins/webreport/webcal.py b/gramps/plugins/webreport/webcal.py
index ecf2773fe..6c43db40b 100644
--- a/gramps/plugins/webreport/webcal.py
+++ b/gramps/plugins/webreport/webcal.py
@@ -71,6 +71,8 @@ from gramps.plugins.lib.libhtml import Html, xml_lang
 from gramps.plugins.lib.libhtmlconst import _CHARACTER_SETS, _CC, _COPY_OPTIONS
 from gramps.gui.pluginmanager import GuiPluginManager
 
+from gramps.gen.lib.date import gregorian
+
 # import styled notes from
 # src/plugins/lib/libhtmlbackend.py
 from gramps.plugins.lib.libhtmlbackend import HtmlBackend
@@ -1727,10 +1729,3 @@ def get_day_list(event_date, holiday_list, bday_anniv_list):
  
     # return to its caller calendar_build()
     return day_list
-
-def gregorian(date):
-    """Convert given date to gregorian. Doesn't modify the original object."""
-    if date.get_calendar() != Date.CAL_GREGORIAN:
-        date = Date(date)
-        date.convert_calendar(Date.CAL_GREGORIAN)
-    return date