It became very popular in the English language after the Norman conquest of England in 1066,[2] and remained so throughout the Middle Ages and into the modern era.

Both ultimately descend from Proto-Germanic *Wiljahelmaz, with a direct cognate also in the Old Norse name Vilhjalmr and a West Germanic borrowing into Medieval Latin Willelmus.

This William is immortalized in the Chanson de Guillaume, and the esteem in which he was held may account for the name's subsequent popularity among European nobility.

The English "William" is taken from the Anglo-Norman language and was transmitted to England after the Norman conquest in the 11th century, and soon became the most popular name in England[citation needed], along with other Norman names such as Robert (the English cognate was Hrēodbeorht, which by regular sound changes would have developed into something along the lines of "Reedbart"[6][7])[better source needed], Richard, Roger (the English cognate was Hroðgar[8]), Henry (all of Germanic origin and may have been transmitted through the Normans' use of Old French).

The name Wilkin/Wilkins is also of medieval origin, taken from the shortened version of William (Will) with the suffix "kin" added.