The study presents an overview of the available information about coins from the territory of the Early Byzantine province of Moesia Secunda between 498 and 681. It is based on a PhD thesis defended in 2019 at St. St. Cyril and Methodius Veliko Tarnovo University, where the author obtained a doctoral degree. In this edition, the author has made certain revisions to expand on ideas and incorporate new research. The book aims to systematise the knowledge of the monetary circulation in Moesia Secunda in the 6th and 7th centuries based on numismatic data. The observations and analyses conducted on the province studied are compared with published information and studies on the Byzantine coin circulation. This comparative approach allows for the development of new concepts and a deeper understanding of the monetary circulation within the entire Byzantine Empire during the period under study.