- Source: Polycarpus II of Byzantium
Polycarpus II (Greek: Πολύκαρπος Βʹ; died c. 144) was the bishop of Byzantium from around 141 until his death in 144. According to ancient sources, he remained in office for seventeen years, but Church historian Nikiforos Kallistos mentions that Polycarpus II was the bishop of Byzantium for three years (141–144 AD). He succeeded Bishop Felix., and his successor was Athenodorus.