ROLLO, like all Scandinavian chiefs, gathered a band of warriors around him. They crewed his ship and fought for him in his early campaigns in Francia. Later they lived in his hall at Rouen and were rewarded for their services from the revenues the city produced and with the lands now at Rollo's disposal. His successors, too, surrounded themselves with young tiros, as Dudo called them, ambitious for fame and reward. In the early eleventh century, when Dudo wrote of them, this body of men and warriors comprised the duke's domus or household. By the first decades of the twelfth century, however, the household had split into two parts: the domus regis and the familia regis. By then, the domus regis was composed of the chancellor, chaplains, bakers, kitchen-staff, and huntsmen while the familia comprised a wider body that included retained knights and their commanders, not all of whom were necessarily present at court permanently and not all of whom were retained, as such. But there was still some overlap between the domus and the familia, as J. O. Prestwich observed in 1981, for the leaders of the familia were also salaried members of the domus, with the offices of the master marshal and the constables, and their stipends, recorded in the Constitutio domus regis.

These two terms, domus regis and familia regis, are most simply translated as ‘the king's house’ and ‘the king's family’, but the emphasis in the narratives on the use of the knights of the familia as garrisons, as shock troops, and as the backbone of ducal armies has led historians to prefer to translate familia regis as ‘military household’. This is somewhat deceptive. Even in the twelfth century, the familia regis was not a military institution per se. Although it included a shifting and assorted collection of young knights hoping to make their name, they did not just fight for the dukes, but might also act as messengers or hunting companions. Their function was not, then, necessarily military. Moreover, the attempt to equate the familia with the household is erroneous, as it suggests that the knights of the familia slept in the duke's hall at Rouen or followed him when he moved around the duchy.