William Swan

(male) Probably the most successful of all the Old French names of Germanic origin that were introduced to England by the Normans. It is derived from Germanic wil ‘will, desire’ + helm ‘helmet, protection’. The fact that it was borne by the Conqueror himself does not seem to have inhibited its favour with the ‘conquered’ population: in the first century after the Conquest it was the commonest male name of all, and not only among the Normans. In the later Middle Ages it was overtaken by John, but continued to run second to that name until the 20th century, when the picture became more fragmented.

Scottish and English: from Middle English swan ‘swan’, hence a nickname for a person noted for purity or excellence (which were taken to be attributes of the swan), or resembling a swan in some other way. This was also an Old Norse and Old English personal name, from which the surname may be derived. In some cases it may be a habitational name for someone who lived at a house with the sign of a swan.