It is far more common for daughters to be missing from the historical records than sons. And Roland de Velville was a person of sufficient prominence that the birth to him of a son would be noticed and mentioned *somewhere*. The most common place of mention would be in a last will and testament, but no such document for de Velville is known to have survived (likely lost during the intervening centuries). In any case, it seems to me unlikely that his daughters would be reasonably well known to history but a son would not. The very great likelihood is that Roland de Velville simply did not have any sons.
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