Francia or Frankia, later also
called the Frankish Empire (Latin: imperium Francorum), Frankish
Kingdom (Latin: regnum Francorum, "Kingdom of the Franks"),
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.