Recorded in many forms as shown below, this is an English medieval surname, but one ultimately of pre 7th century Olde French origins. It is occupational and derives from the word "peseor" meaning to weigh, and was probably introduced into England immediately after the Norman Invasion of 1066. A peiser was the medieval equivalent of a Weights and Measures or Trading Standards inspector, although one with more powers. A peiser could order the arrest and trial of manufacturers and shopkeepers found to be supplying inadequate goods. The word poise remains a slang word in parts of the North of England, and it means basically "to kick or knock away". The modern spelling list includes such forms as Poyser, Poynser, Poyzer, Peiser, Peizer, Piser, Pizer, Pyser, Pyzer and Pozer, and the early name development includes: Elyas Poyser in the pipe rolls of the county of Yorkshire in 1219, Josceus le Pesur of Kent in 1224, and John Poser in the Subsidy Rolls of Sussex in 1296. The first recorded spelling of the family name is probably that of Simon le Pesur. This was dated 1198, in the Pipe Rolls of Kent during the reign of King Richard 1st of England, known as "The Lionheart", 1189 - 1199. Surnames became necessary when governments introduced personal taxation. In England this was sometimes known as the Poll Tax. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.