* calc/calc.el (calc-gregorian-switch): In menu, put dates before regions.

This is easier to follow, lines up better in the menu, and lets us
coalesce regions that switch at the same time.  Give country
names, not "Vatican", as that's better for non-expert users.  Use
names that are stable between the date of switch and now, e.g.,
Bohemia and Moravia (which existed then and now) and not
Czechoslovakia (which didn't exist then and doesn't exist now).
What is now the U.S. mostly did not switch at the same time as
Britain, so omit the U.S.  Correct spelling of "Britain".
Catholic Switzerland was too much of a mess, so omit it.

1 files changed, 12 insertions, 13 deletions

diff --git a/lisp/calc/calc.el b/lisp/calc/calc.el
index ff4e5d71dce..58eabf9bcec 100644
--- a/lisp/calc/calc.el
+++ b/lisp/calc/calc.el
@@ -2040,24 +2040,23 @@ complicated.  Also, the boundaries of the countries were different at
 the times of the calendar changes than they are now.
 The Vatican decided that the Gregorian calendar should take effect
 on 15 October 1582 (Gregorian), and many Catholic countries made
-the change then.  Great Britian and its colonies had the Gregorian
+the change then.  Great Britain and its colonies had the Gregorian
 calendar take effect on 14 September 1752 (Gregorian); this includes
 the United States."
   :group 'calc
   :version "24.4"
   :type '(choice (const :tag "Always use the Gregorian calendar" nil)
-                 (const :tag "Great Britian and the US (1752 9 14)" (1752 9 14 639797))
-                 (const :tag "Vatican (1582 10 15)" (1582 10 15 577736))
-                 (const :tag "Czechoslovakia (1584 1 17)" (1584 1 17 578195))
-                 (const :tag "Denmark (1700 3 1)" (1700 3 1 620607))
-                 (const :tag "France (1582 12 20)" (1582 12 20 577802))
-                 (const :tag "Hungary (1587 11 1)" (1587 11 1 579579))
-                 (const :tag "Luxemburg (1582 12 25)" (1582 12 25 577807))
-                 (const :tag "Romania (1919 4 14)" (1919 4 14 700638))
-                 (const :tag "Russia (1918 2 14)" (1918 2 14 700214))
-                 (const :tag "Sweden (1753 3 1)" (1753 3 1 639965))
-                 (const :tag "Switzerland (Catholic) (1584 1 22)" (1584 1 22 578200))
-                 (const :tag "Switzerland (Protestant) (1701 1 12)" (1701 1 12 620924))
+                 (const :tag "1582-10-15 - Italy, Poland, Portugal, Spain" (1582 10 15 577736))
+                 (const :tag "1582-12-20 - France" (1582 12 20 577802))
+                 (const :tag "1582-12-25 - Luxemburg" (1582 12 25 577807))
+                 (const :tag "1584-01-17 - Bohemia and Moravia" (1584 1 17 578195))
+                 (const :tag "1587-11-01 - Hungary" (1587 11 1 579579))
+                 (const :tag "1700-03-01 - Denmark" (1700 3 1 620607))
+                 (const :tag "1701-01-12 - Protestant Switzerland" (1701 1 12 620924))
+                 (const :tag "1752-09-14 - Great Britain and dominions" (1752 9 14 639797))
+                 (const :tag "1753-03-01 - Sweden" (1753 3 1 639965))
+                 (const :tag "1918-02-14 - Russia" (1918 2 14 700214))
+                 (const :tag "1919-04-14 - Romania" (1919 4 14 700638))
                  (list :tag "(YEAR MONTH DAY)"
                        (integer :tag "Year")
                        (integer :tag "Month (integer)")