When Charlemagne decide to travel to Rome for important business in 780, he took his wife, Hildegard, with him, and she likely did more than provide companionship.
She was an Agilolfing, a member of the powerful, established family that ruled Bavaria. And if she was like most medieval women, she wanted the inheritance to go her sons, not the offspring from Charles’s first marriage.
At that time, Charles had reigned 12 years and was 32, no longer a young man by medieval standards. It might have been time to think about their children’s future. When Charles and Hildegard reached Rome in 781, their two youngest boys, ages 3 and 4, were anointed subkings, and their 6-year-old daughter was betrothed to the child emperor of Byzantium.
Another indication that the royal couple was thinking long term: when they returned to Francia, they brought scholars with them. If they wanted their subjects, and their enemies, to associate their realm with ancient Rome, they needed intellectuals. For more about learned men in Charles’s court, see my post in Unusual Historicals.