<P> In 884, Charles the Fat reunited all the kingdoms for the last time, but he died in 888 and the empire immediately split up . With the only remaining legitimate male of the dynasty a child, the nobility elected regional kings from outside the dynasty or, in the case of the eastern kingdom, an illegitimate Carolingian . The illegitimate line continued to rule in the east until 911, while in the western kingdom the legitimate Carolingian dynasty was restored in 898 and ruled until 987 with an interruption from 922 to 936 . </P> <P> The size of the empire at its inception was around 1,112,000 square kilometres (429,000 sq mi), with a population of between 10 and 20 million people . To the south it bordered the Emirate of Córdoba and, after 824, the Kingdom of Pamplona; to the north it bordered the kingdom of the Danes; to the west it had a short land border with Brittany, which was later reduced to a tributary; and to the east it had a long border with the Slavs and the Avars, who were defeated and their land incorporated into the empire . In southern Italy, the Carolingians' claims to authority were disputed by the Byzantines (eastern Romans) and the vestiges of the Lombard kingdom in the Principality of Benevento . </P> <P> Use of the term "Carolingian Empire" is a modern convention . The language of official acts in the empire was Latin . The empire was referred to variously as universum regnum ("the whole kingdom", as opposed to the regional kingdoms), Romanorum sive Francorum imperium ("empire of the Romans and Franks"), Romanum imperium ("Roman empire") or even imperium christianum ("Christian empire"). </P> <P> Though Charles Martel chose not to take the title King, as his son Pepin III the Short would, or Emperor, as his grandson Charlemagne would become titled, he was absolute ruler of virtually all of today's continental Western Europe north of the Pyrenees . Only the remaining Saxon realms, which he partly conquered, Lombardy, and the Marca Hispanica south of the Pyrenees were significant additions to the Frankish realms after his death . </P>

The carolingians came to power in which frankish territory