Francia, also called the Kingdom of the Franks, or Frankish Empire was the largest post-Roman Barbarian kingdom in Western Europe. It was ruled by the Franks during Late Antiquity and the Early Middle Ages.
The core Frankish territories inside the Roman empire were close to the Rhine and Maas rivers in the north. After a period where small kingdoms inter-acted with the remaining Gallo-Roman institutions to their south, a single kingdom uniting them was founded by Clovis I who was crowned King of the Franks in 496. Under the nearly continuous campaigns of Pepin of Herstal, Charles Martel, Pepin the Short, Charlemagne, and Louis the Pious—father, son, grandson, great-grandson and great-great-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. 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 in northern Europe.