This study compares the published data from notarial deeds drawn up in Licostomo with previously unpublished information extracted from the financial registers of the treasury (Massaria) of Caffa. Its main objective is to reconstruct the networks of merchants who expanded their commercial activities between the mouths of the Danube and the Crimean Peninsula in the second half of the fourteenth century. This comparative approach has made it possible to identify a series of Genoese merchants active between Caffa and Licostomo in the 1370s and 1380s, while also offering new perspectives on the conflict between the Genoese and Dobrotich, on the administration of the trading post of Licostomo, and on the diplomatic relations between Caffa and Moldavia. Based on a detailed examination of three accounting registers of the treasury of Caffa, covering the financial years 1374–1375, 1381–1382, and 1386–1387, this research provides a new edition of several excerpts from these registers, shedding light on the relations between Caffa and the trading posts of the northwestern Black Sea.