Originally, the core Frankish territories inside the former Western Roman Empire were located close to the Rhine and Meuse rivers in the north, [ 6 ] but Frankish chiefs such as Chlodio would eventually expand their influence within Roman territory as far as the Somme river in the 5th century. Childeric I , a Salian Frankish king, was one of several military leaders commanding Roman forces of various ethnic affiliations in the northern part of what is now France.
His son, Clovis I , succeeded in unifying most of Gaul under his rule in the 6th century by notably conquering Soissons in and Aquitaine in following the collapse of the Western Roman Empire, as well as establishing leadership over all the Frankish kingdoms on or near the Rhine frontier; thus founding what would come to be known as the Merovingian dynasty. The dynasty subsequently gained control over a significant part of what is now western and southern Germany.
It was by building upon the basis of these Merovingian deeds that the subsequent Carolingian dynasty— through the nearly continuous campaigns of Pepin of Herstal , his son Charles Martel , grandson Pepin the Short , and great-grandson Charlemagne — secured the greatest expansion of the Frankish state by the early 9th century.
Charlemagne also received the Roman imperial crown in , thus creating the Frankish-Roman Empire , [ 7 ] which is also referred to as the Carolingian Empire , or just the Frankish Empire Latin : Imperium Francorum. During the reign of the Merovingian and Carolingian dynasties, the Frankish realm was one large polity , generally subdivided into several smaller kingdoms ruled by different members of the ruling dynasties.
Whilst these kingdoms coordinated, they also regularly came into conflict with one another. The old Frankish lands, for example, were initially contained within the kingdom of Austrasia , centred on the Rhine and Meuse , roughly corresponding to later Lower Lotharingia.
