Phoulloi (Greek: Φοῦλλοι), also known as Phoulla or Phoullai (Φοῦλλα[ι]; Ukrainian: Фули, romanized: Fuly, Фул, Ful, or Фула, Fula), was a Byzantine-era city in the southern Crimea.
[1] According to O. Pritsak in the Oxford Dictionary of Byzantium, "it was probably located on the trans-Crimean route, approximately halfway between Cherson and Cimmerian Bosporos".
It occurs next in the hagiography of the late 8th-century saint John of Gothia, who was held prisoner in the city in 787, and baptized and cured the child of the local lord, before escaping to Amastris.
In the 9th century, the hagiography of Constantine the Philosopher mentions the "nation of Phoulloi", who venerated an oak tree and were ruled by an elder.
[1] The Notitiae Episcopatuum of the Patriarchate of Constantinople in the late 8th and 9th centuries record that the bishop of the Khazars (Chotziroi) resided near Phoulloi and another place with the Turkic name Kara Su ("Black Water"), hellenized as Charasion (Χαράσιον) or translated as Mabron Neron (Μάβρον Νερὸν) in the Notitiae.