By the time of Karl (Charlemagne) it was traditional among the Franks for the kingdom to be divided between living sons. Karl himself inherited only half the kingdom; his brother Karlmann inherited the other half. Karlmann only ruled for three short years, and almost went to war against Karl, before suffering a timely death. Karl then annexed his brother's lands disposessing his nephews.

His grandfather had ruled the Frankish kingdom, de facto if not in name, also divided the kingdom between his sons Pepin, Karlmann, and Grifo. Pepin first forced Grifo into a monastery. Karlmann followed shortly after, and apparently more willingly, leaving Pepin as the sole Mayor of Palace and able to claim the actual crown.

Even prior to the Carolingians, the Merovingians usually split the Frankish kingdom upon their deaths. A man who wanted to rule a united Franconia, almost always had to unite it himself, usually over the corpses of their brothers or close relatives. The Frankish kingdom was usually a collection of kingdoms with multiple kings. Karl would have gone against centuries of tradition had he tried to elevate only one heir. All his heirs were due an equal (or at least fair) slice of his empire.