This cross is sometimes
called Portuguese cross. It was the sign on the standard of the Grand Master
of the Teutonic Crusaders' Order used in the battle of
Grünwald, Tannenberg, in 1410, against the Poles, where the Teutonic
knights were defeated. It was a common cross form on crusader
knights' coats of arms during the Middle Ages.
See also the crutch cross, , in Group 28.