1. The last issues of Tyras’ mint date from the reign of the Roman emperor Alexander Severus, who died in A.D. 235. Possibly the Goths captured the city a few years later. Cf. Minns, E. H., Scythians and Greeks (Cambridge 1913), pp. 447-448, who does not state clearly whether the city was destroyed. Rostovtzeff M., Iranians and Greeks in South Russia (Oxford 1922), pp. 216-217, claims that the city survived its capture by the Goths, but gradually declined.
2. Κωνσταντίνος Πορφυρογέννητος, Πρὸς τὸν ἴδιον υἱὸν Ρωμανόν, Moravcsik G. - Jenkins R. J. H. (eds.), Constantine Porphyrogenitus, De Administrando Imperio (Corpus Fontium Historiae Byzantinae 1, Washington 1967) ch. 37, 58-67. The same etymology lies behind the place-name’s Rumanian (Cetatea Albă), Russian (Belgorod), Ukrainian (Bilhorod) and Turkish (Akkerman) versions, while Byzantine historian Λαόνικος Χαλκοκονδύλης, Ἀποδείξεις Ἱστοριῶν δέκα, Darkó E. (ed.), Laonici Chalcocondylae Historiarum Demonstrationes 1 (Budapest 1922) p. 125, 4-5 atticizes the mediaeval place-name into «Leucopolichnē».
3. Honigmann, E., “Studies in Slavic Church History”, Byzantion 17 (1944-1945), pp. 158-162, who is mistaken in believing that the bishopric was short-lived, whereas in reality it is mentioned by sources (now as bishopric of Asprokastron) in the following centuries: see Andreescu, Ş., The Metropolitanate of Halicz and the Bishopric of Asprokastron. A few considerations (Études byzantines et post-byzantines 4, Iaşi 2001).
4. Honigmann, E., “Studies in Slavic Church History”, Byzantion 17 (1944-1945), pp. 159-161. Bromberg, J., “Toponymical and Historical Miscellanies on Medieval Dobrudja, Bessarabia and Moldo-Wallachia”, Byzantion 13 (1938), pp. 50-68 mistakenly believes that the Italian place-name Moncastro did not derive from Mavrokastron/Maurocastro, but from a supposed corruption of Albocastro = Asprokastron.
5. On Niconia opposite Tyras, see Minns, E. H., Scythians and Greeks (Cambridge 1913), p. 14. The place-name “Mavrokastron” is mentioned also in the so-called “Toparcha Gothicus”, but, as it was proven by Ševčenko, I., “The Date and Author of the So-Called Fragments of Toparcha Gothicus”, Dumbarton Oaks Papers 25 (1971), pp. 115-188, the text is an early nineteenth-century forgery.
6. Browning, R., “Asprokastron”, in A. Kazhdan (ed.), The Oxford Dictionary of Byzantium 1 (New York - Oxford 1991), p. 212. Since all contemporary Italian sources mention the city’s name as Maurocastrum or Moncastro, we must assume that the Genoese trading post was not situated on Asprokastron per se, but on Mavrokastron, on the opposite bank.
7. Browning R., “Asprokastron”, in A. Kazhdan (ed.), The Oxford Dictionary of Byzantium 1 (New York - Oxford 1991), p. 212, dates the capture of Asprokastron by the Ottomans in the year 1485.