A city-state is a sovereign state that consists of a city and its dependent territories. Historically, this included cities such as Rome, Athens, Carthage, and the Italian city-states during the Renaissance—but today only a handful of sovereign city-states exist, with some disagreement as to which are city-states. A great deal of consensus exists that the term properly applies to Singapore, Monaco, and Vatican City.
A number of other small states share similar characteristics, and therefore are sometimes also cited as modern city-states. Namely, Qatar,Brunei,Kuwait,Bahrain, and Malta, which each have an urban center comprising a significant proportion of the population, though, all have several distinct settlements and a designated or de facto capital city. Occasionally, other small states with high population densities, such as San Marino, are also cited, despite lacking a large urban centre characteristic of traditional city-states.
Several non-sovereign cities enjoy a high degree of autonomy, and are sometimes considered city-states. Hong Kong and Macau, along with independent members of the United Arab Emirates, most notably Dubai and Abu Dhabi, are often cited as such.
Historical city-states included the oldest known Sumerian cities of Uruk and Ur; Ancient Egyptian city-states, such as Thebes and Memphis; the Phoenician cities (such as Tyre and Sidon); the Berber city-states of the Garamantes; the city-states of ancient Greece (the poleis such as Athens, Sparta, Thebes, and Corinth); the Roman Republic (which grew from a city-state into a great power); the Mayan and other cultures of pre-Columbian Mesoamerica (including cities such as Chichen Itza, Tikal, Copán and Monte Albán); the central Asian cities along the Silk Road; the city-states of the Swahili coast; Venice; Ragusa; states of the medieval Russian lands such as Novgorod and Pskov; and many others. Scholars have classed the Viking colonial cities in medieval Ireland, most importantly Dublin, as city-states.