Flag of Greece Byzantine double-headed eagle (see below), the cross, depictions of saints and various mottoes. The Christian Greek sipahi cavalry employed by the Ottoman Sultan were allowed to use their own, clearly Christian flag, when within Epirus and the Peloponnese. It featured the classic blue cross on a white field with the picture of St. George slaying the dragon, and was used from 1431 until 1639, when this privilege was greatly limited by the Sultan. Similar flags were used by other local leaders. The closest to a Greek "national" flag during Ottoman rule was the so-called "Graeco-Ottoman flag" (Γραικοθωμανική παντιέρα), a civil
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