Francia or Frankia, also called the Kingdom of the Franks or Frankish Kingdom (Latin: regnum Francorum), Frankish Realm or occasionally Frankland, was the territory inhabited and ruled by the Franks from the 3rd to the 10th century. Under the nearly continuous campaigns of Charles Martel, Pepin the Short, and Charlemagne—father, son, grandson—the greatest expansion of the Frankish empire was secured by the early 9th century.
The tradition of dividing patrimonies among brothers meant that the Frankish realm was ruled, nominally, as one polity subdivided into several regna (kingdoms or subkingdoms). The geography and number of subkingdoms varied over time, but the particular term Francia came generally to refer to just one regnum, that of Austrasia, centred on the Rhine and Meuse rivers in northern Europe; even so, sometimes the term was used as well to encompass Neustria north of the Loire and west of the Seine. Eventually, the singular use of the name Francia shifted towards Paris, and settled on the region of the Seine basin surrounding Paris, which still today bears the name Île-de-France, and which region gave its name to the entire Kingdom of France.