The given name Jefferey originates from the Germanic name Geoffrey, which is derived from the Old French name Geoffroi. This name itself comes from the Old German words "gau" meaning "territory" and "frid" meaning "peace," essentially translating to "peaceful territory." The name became popular in medieval Europe, particularly in England and France.

One of the earliest recorded instances of the name Jefferey can be found in the Domesday Book, a comprehensive survey of landowners in England commissioned by William the Conqueror in 1086. The name Geoffrey is mentioned several times in this historical record, indicating its presence in England during the Norman era.

The name gained further prominence in the 12th century due to Geoffrey of Monmouth, a Welsh cleric and one of the most influential chroniclers of British history. His work, Historia Regum Britanniae (History of the Kings of Britain), written around 1136, popularized the legend of King Arthur and the Knights of the Round Table, contributing to the enduring fame of the name Geoffrey.

In the 13th century, the name was borne by Geoffrey Chaucer, the renowned English poet and author of the Canterbury Tales. Chaucer, who lived from around 1343 to 1400, is considered the father of English literature and his use of the name further cemented its prestige.

Another notable figure with the name Jefferey was Geoffrey Plantagenet, Count of Anjou, born around 1113. He was the father of King Henry II of England and played a significant role in the political landscape of medieval Europe.

During the Renaissance period, the Italian scholar and humanist Geoffrey Tory, born around 1480, made contributions to the development of typography and book design, further adding to the name's historical significance.

While the spelling variation "Jefferey" emerged later, it is important to note that throughout history, the name has been spelled in various ways, including Geoffrey, Jeffry, and Jeffery, reflecting the evolution of language and regional variations.