This interesting surname is of English locational origin from "Birkby", the name of two places in Cumberland and one in Yorkshire. Birkby near Maryport, Cumberland was called "Brettebi" in the Poll Tax of 1163, while Birkby near Ravenglass in the same county was recorded "Bretteby" in the Placita de quo Warranto dated 1292, and the place of the same name in Yorkshire was written as "Bretebi" in the Domesday Book of 1086. The place name is composed of the Old Norse "Bretabyr", the settlement (byr) of the Brittons (Brettas). The name is found widespread in Yorkshire. Agnes, daughter of Xpofer Byrkbey was christened at Rothwell, Yorkshire on August 31st 1549, while Margaret Birkbie married Thomas Brown at St. Olave, York on August 28th 1585. At St. Mary Whitechapel in London, Robert the son of James and Ellen Byrkby was christened on January 16th 1623. Anne Birkby married Johannes Dickonson at Kippax on October 20th 1664. The first recorded spelling of the family name is shown to be that of Antoni Byrkby, which was dated May 8th 1544, christening witness at Kippax, Yorkshire, during the reign of King Henry V111, "Good King Hal", 1509 - 1547. Surnames became necessary when governments introduced personal taxation. In England this was known as Poll Tax. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.