diff --git a/gramps/gen/lib/date.py b/gramps/gen/lib/date.py
index db344aefc..a5c6a694e 100644
--- a/gramps/gen/lib/date.py
+++ b/gramps/gen/lib/date.py
@@ -1635,6 +1635,14 @@ class Date(object):
         if modifier != Date.MOD_TEXTONLY:
             sanity = Date(self)
             sanity.convert_calendar(self.calendar, known_valid = False)
+            # convert_calendar resets slash and new year, restore these as needed
+            if sanity.get_slash() != self.get_slash():
+                sanity.set_slash(self.get_slash())
+            if self.is_compound() and sanity.get_slash2() != self.get_slash2():
+                sanity.set_slash2(self.get_slash2())
+            if sanity.get_new_year() != self.get_new_year():
+                sanity.set_new_year(self.get_new_year())
+                sanity._adjust_newyear()
 
             # We don't do the roundtrip conversion on self, becaue
             # it would remove uncertainty on day/month expressed with zeros
@@ -1642,29 +1650,27 @@ class Date(object):
             # Did the roundtrip change the date value?!
             if sanity.dateval != value:
                 try:
-                    if sanity.get_new_year() != self.get_new_year():
-                        # convert_calendar resets the new year, so the date value will differ.
-                        # Just check the sort value matches then.
-                        if self.sortval != sanity.sortval:
-                            raise DateError("Invalid date value {}".format(value))
-                    else:
-                        # Maybe it is OK because of undetermined value adjustment?
-                        zl = zip(sanity.dateval, value)
-                        # Loop over all values present, whether compound or not
-                        for d,m,y,sl in zip(*[iter(zl)]*4):
-                            # each of d,m,y,sl is a pair from dateval and value, to compare
-                            for adjusted,original in d,m:
-                                if adjusted != original and not(original == 0 and adjusted == 1):
-                                    raise DateError("Invalid day/month {} passed in value {}".
-                                            format(original, value))
+                    # Maybe it is OK because of undetermined value adjustment?
+                    zl = zip(sanity.dateval, value)
+                    # Loop over all values present, whether compound or not
+                    for d,m,y,sl in zip(*[iter(zl)]*4):
+                        # each of d,m,y,sl is a pair from dateval and value, to compare
+                        adjusted,original = sl
+                        if adjusted != original:
+                            raise DateError("Invalid date value {}".
+                                    format(value))
 
-                            adjusted,original = y
-                            adjusted -= year_delta
+                        for adjusted,original in d,m:
                             if adjusted != original and not(original == 0 and adjusted == 1):
-                                raise DateError("Invalid year {} passed in value {}".
+                                raise DateError("Invalid day/month {} passed in value {}".
                                         format(original, value))
 
-                            # ignore slash difference
+                        adjusted,original = y
+                        adjusted -= year_delta
+                        if adjusted != original and not(original == 0 and adjusted == 1):
+                            raise DateError("Invalid year {} passed in value {}".
+                                    format(original, value))
+
                 except DateError:
                     log.debug("Sanity check failed - self: {}, sanity: {}".format(
                         self.to_struct(), sanity.to_struct()))