Flag of Greece los reynos" depicts the flag of "the Empire of Constantinople" combining the red-on-white Cross of St George with the "tetragrammatic cross" of the ruling house of the Palaiologoi, featuring the four betas or "pyrekvola" ("fire-steels") on the flag quarters representing the imperial motto Βασιλεύς Βασιλέων Βασιλεύων Βασιλευόντων ("King of Kings Reigning over those who Rule"). The tetragrammatic cross flag, as it appears in quarters II and III in this design, is well documented. In the same Spanish atlas this "plain" tetragrammatic cross flag is presented as (among other places in the Empire) "the Flag of Salonika" and "the real Greece
Flag of Greece other designs surviving until that time. No other designs and badges can be shown on the flag. To date, no specification of the exact shade of the blue colour of the flag has been issued. Consequently, in practice hues may vary from very light to very dark. The Greek Flag Day is on 27 October. The old land flag is still flown at the Old Parliament building in Athens, site of the National Historical Museum, and can still be seen displayed unofficially by private citizens. The use of the Greek flag is regulated by Law 851. More specifically, the law