Theoleptos of Philadelphia was a prominent Byzantine monk, mystic, and theologian who served as the Metropolitan of Philadelphia from approximately 1284 until his death in 1322. Born in Nicaea around 1250, he transitioned from a married deacon to an ascetic monk following the religious shifts of his era. As a significant political and religious figure during the Palaiologan period, he was a staunch opponent of church unions and a defender of Orthodox traditions. He is recognized as a saint within the Eastern Orthodox Church for his spiritual leadership and theological contributions.