The English-language surname Prosser is considered to be a Welsh surname. The name originated as an Anglicisation of the Welsh-language ap Rhosier, or ap Rosser, both meaning son of Roger. The English-language personal nameRoger is derived from the Old French personal name Roger, Rogier. This personal name is of Germanic origin, derived from the elements hrōd and gār, gēr. The Old French name was adopted by the Normans, and was introduced into Britain by them in the Middle Ages. The name became one of the most popular masculine names in the Middle Ages, and lost popularity afterwards. Until the Tudor period Welsh names generally took the format X son of Y, or X daughter of Y. The Old Welsh word for son was map, which later lost the initial letter to become ap. Although some of the Welsh gentry began to adopt the English fashion for hereditary surnames even before the Act of Union between England and Wales in 1536, in general the Act marked the beginning of a gradual shift towards hereditary surnames in Wales that was not complete until the 18th century. In some cases ap was merged into the following personal name to create an hereditary name. So Ap Richard became Pritchard, ap Even became Bevan and ap Hugh emerged as Pugh. The shift from ap Rosser to Prosser is of this pattern, though the surname Rosser also occurs. The distribution of Prosser and Rosser in 1842-46 was strongly centred in south-east Wales, and largely absent from other parts of Wales. Early examples of the surname include:
1529 Richard ap Rosser was a party to two deeds relating to 'a mansion place called the Van' in Senghenydd.
1556 Morgan Lewis ap Rosser was a party to a grant of land in Llywell, Co. Brecon.
Name distribution
There are various sources for surname maps charting the geographic distribution of surnames.
England and Wales
's distribution map, based on their data from the 1891 England and Wales Census, shows Prossers are strongly present in southeast Wales and the western counties of England. Particularly high concentrations are in the Welsh historic counties of Glamorgan and Monmouthshire and the English county of Herefordshire, which each have more than 352 Prosser families.
Germany
German Prossers are primarily found in southern Germany, with 32.7% of Prossers residing in Bavaria, and 31.4% of Prossers residing in Baden-Württemberg.
Italy
The Italian Gens Project shows there are a small number of Prossers living in Italy. Their distribution map results show that the Prossers are concentrated in the northernmost province, Alto Adige/Südtirol.
United States
Current distribution maps from the Gens Project in the United States based on the 2000 US census demonstrate that the name is most common in eight states: California, Florida, Georgia, Illinois, New York, Ohio, Pennsylvania, and South Carolina, while still numbering less than a thousand individuals in each of those states. has a surname map for the name's distribution according to the United States Census for 1920. At that time, the name Prosser was most common in six states: California, Illinois, New York, Ohio, Pennsylvania, and South Carolina, with a total of 93-183 Prosser households in each state. Using data based on 142 Prosser immigrants to New York, the vast majority departed from Great Britain, while 11 are from Ireland and 21 from Germany.
