Why did Henry I father more children than any other English monarch?
With nine sons and 11 daughters from at least seven mothers, it was suggested by his contemporary, the historian William of Malmesbury, that he needed the children.
Kathleen Thompson, an independent scholar, has asked whether this often ridiculed view might contain some truth, considering the strategic way Henry used his illegitimate offspring.
Alliances were fostered when his daughters became the countess of the Perche in France, the duchess of Brittany and even the queen of Scotland, while his sons became important and useful nobles.
Henry's sexual partners were selected from all the races he ruled, including a Norman widow; two Englishwomen, one from the rebellious north; the daughter of a Welsh prince; a Franco-Norman aristocrat; and a Norman from the Welsh marches. His wife was the Scottish princess Edith Matilda, descended from the old English royal lines.
Yet Thompson doubts Henry's liaisons were attempts to build links with the peoples he ruled. At the very end of the 11th century, Henry had few expectations of power - his older brothers William and Robert inherited the kingdom of England and Duchy of Normandy, while he was merely given a sum of money.
It was at this time that the rootless Henry was fathering many of his brood.
Yet in 1100, Henry had himself proclaimed king of England after William was killed in the New Forest while Robert was away crusading. Six years later he took Normandy, too. Then the illegitimate children came in handy for alliances and allies.
Henry might have been a prototype for the aristocratic bounder, but the consummate politician remembered his offspring.