In the medieval Bulgarian state, Roman law was never applicable. However, in the Middle Ages it has exerted a great influence on Bulgarian law. Roman law has influenced the legislation of the Medieval Bulgarian state by Byzantium. Although Roman law has never been a valid law in Bulgaria, but many of its principles and norms have been adopted - sometimes with significant changes and deviations from the Bulgarian feudal law. The sources of the Medieval Bulgarian law created on the basis of Roman law are: Byzantine Ecloga, Slavic Ecloga, and The Law for Judging People, as well as the Farmer's Law ware applied at the time of the First Bulgarian state. They were used during the Second Bulgarian state along with the Syntagma of the Matthew Blastares and Royal charters. Roman law affects our legal institutes and institutions of the Bulgarian feudal law. Roman law has influenced the law of medieval Bulgaria through the influence of Byzantium.