The thesis presents the results of a study of 1005 graffiti on 13th century Byzantine amphorae from a shipwreck in the Bay of Sudak near Novy Svet, Crimea, Ukraine. The primary goals of this thesis are 1) to provide an overview of the excavation and shipwreck, 2) to examine the importance of the Novy Svet wreck in terms of Black Sea maritime trade in the Late Byzantine period, 3) to present the data collected at the Center for Underwater Archaeology at the Taras Shevchenko National University in Kiev, Ukraine (CUA) about the graffiti inscribed on the Günsenin IV amphorae raised from the Novy Svet wreck and 4) to discuss the meaning and importance of the graffiti, both aboard the ship itself and in a more general context. The thesis introduces the results of the 2002-2008 underwater excavation seasons at Novy Svet. Excavators have identified a 13th century shipwreck filled with glazed ceramics and amphorae as a Pisan vessel sunk on August 14, 1277. The majority of the amphorae are Günsenin IV jars and have graffiti inscribed on them. Analysis of the graffiti focuses on the division of the marks into morphological categories, and identifying parallels for the specific forms at other archaeological sites. The graffiti are divided into 5 types; Greek/Cyrillic letters, Turkic runes, geometric or pictorial symbols, numerical designations, and Arabic letters. Their parallels speak to a multi-lingual, multi-ethnic trade network in the Black Sea that included Byzantine Greeks, Hellenized Bulgarians, and Arabs.