ORDO BYZANTINUS SANCTI SEPULCHRI [OBSS] is a sovereign, Dynastic Order of Chivalry which recalls the values of Christian Chivalry and forms part of the historical heritage of religious-chivalric Orders, particularly the Greek-Orthodox Order of the Holy Sepulchre, the first Order of the Byzantine Empire founded in theA.D. 325 by Constantine the Great, son of St. Helen.
It traces its regeneration, to the fall of Constantinople, Capital of the Byzantine Empire, on 29th May 1453. This event severed the bonds between Eastern and Western Christendom and brought to the fore the „political“ vocation of the Russian Grand Dukes who granted assistance and protection to the wandering and dispersed Knights of the Holy Sepulchre, who had fought in the various Crusades for the liberation of the Holy Land and to defend the Holy Sepulchre from the Ottomans. These included the Orthodox Crusaders who had militated in the Order of Saint Catherine of Mount Sinai since 1063
The marriage in 1472 between Zoe‘ [Sofia] Paleologina, niece of the last Emperor of Byzantium Constantine XI Paleologo, and Ivan III Velichy [the Great] Grand Duke of Russia, brought to the Imperial House of Russia – as the Bride’s dowry – the title of Pretender to the Throne of Byzantium and encouraged the absorption of many noble Houses and Chivalric Orders founded during the Byzantine Empire.