Righteous
Righteous Gelasius I of Rome (Orthodox veneration unconfirmed)
Папа Римский 492-†496
Gelasius I is a real historical Pope of Rome (492-496), direct successor to Felix III, who continued the confrontation with Constantinople within the Acacian Schism and formulated the doctrine of the separation of spiritual and temporal authority (the "doctrine of the two powers"); his veneration in the Orthodox Church is unconfirmed — the Orthodox Encyclopedia itself calls him a "saint" only with reference to the Western calendar.
Gelasius I held the Roman see from March 492 to November 21, 496, as the direct successor to Pope Felix III (already researched and found to lack confirmed Orthodox veneration). He continued the line of confrontation with Constantinople within the Acacian Schism, opposing the compromise "Henotikon" of Emperor Zeno. He formulated a doctrine influential for Western theology on the separation of spiritual and temporal authority (the "doctrine of the two powers" — auctoritas sacrata pontificum and regalis potestas), which became one of the early justifications for papal primacy, rejected by Orthodox ecclesiology.
IMPORTANT CAVEAT: the Orthodox Encyclopedia's own article on Gelasius I (pravenc.ru) explicitly labels him "a saint (Western commemoration Nov. 21)" — that is, a saint exclusively of the Western (Catholic) calendar. Azbyka.ru's name-index for "Gelasius" lists only two other saints bearing this name (Gelasius, one of the Ten Martyrs of Crete, and Gelasius the Comedian) — Pope Gelasius I is absent from this list. Thus, Gelasius I's veneration in the Orthodox Church is unconfirmed, independently of his predecessor Felix III's status, even though both popes belong to the same era of church schism with Constantinople.