The Republic of Genoa was a medieval and early modern maritime republic from the years 1099 to 1797 in Liguria on the northwestern Italian coast. During the Late Middle Ages, it was a major commercial power in both the Mediterranean Sea and the Black Sea. Between the 16th and 17th centuries, it was one of the major financial centers in Europe.

The maritime republics, also called merchant republics, were Italian thalassocratic port cities which, starting from the Middle Ages, enjoyed political autonomy and economic prosperity brought about by their maritime activities. The term, coined during the 19th century, generally refers to four Italian cities, whose coats of arms have been shown since 1947 on the flags of the Italian Navy and the Italian Merchant Navy: Amalfi, Genoa, Pisa, and Venice. In addition to the four best known cities, Ancona, Gaeta, Noli, and, in Dalmatia, Ragusa, are also considered maritime republics; in certain historical periods, they had no secondary importance compared to some of the better known cities.