The study of Florentine-Hungarian economic relations in the first half of the fifteenth century provides a challenging opportunity to survey late medieval social and economic strategies and their adjustment to a specific regional situation. Florentine merchants were actively present with their trading and banking activity in medieval Europe whereas medieval Hungary played a notable role in the political and economic landscape of East-Central Europe during the reign of King Sigismund of Luxemburg (1387-1437). Based on a prosopographic database the study investigates these businessmen's economic and social background in Florence via in-depth case studies and quantitative research. Concentrating further on the community of foreign traders in Buda as a royal seat in formation, the study reviews also the competition between South German and Florentine traders. An appendix includes the complete prosopographic database compiled for this research, being a collective biography of Florentine merchants and investors working in Hungary in the first half of the fifteenth century. Secondly it includes a list of business partners and transactions in Hungary in the debtors lists of the Florentine Catasto Records.