British historian Jonathan Riley-Smith, in his work, examines the Order of the Brothers of the Jerusalem Hospital of St. John the Baptist (this is the full name of the Order of Hospitallers) in two aspects: as the most important social institution of European settlements on the eastern coast of the Mediterranean Sea and as a knightly order of the Roman Catholic Church , whose influence spread throughout the Christian world. The author pays special attention to the primary task of the order - financial and material support of the Convention in Jerusalem, Acre and Limassol.