This interesting name is of Medieval English origin and is locational from places so called in Dorset, Northants and Somerset. The derivation of this is from the Old English pre 7th Century "Coerse", meaning (water) cress, with "Well(a)", spring or stream. The earliest recording of the place in Northants is in the Curia Rolls of 1196 and appears as "Karswell", and the place in Dorset is recorded as "Cressewell" in the Pipe Rolls of 1186, and in the Feudal Aids Rolls of 1316 as "Carsewelle". During the Middle Ages, when it was becoming more usual for people to migrate from their birthplace to seek work elsewhere, they would often adopt the placename as a means of identification, thus resulting in the wide dispersal of the name. The records of the christenings of two sons of one William Caswell in St. James', Garlickhythe, London are as follows: Edmond Caswell on May 28th 1570 and Robert Caswell on May 6th 1571. The first recorded spelling of the family name is shown to be that of Basilia de Caswella, which was dated 1165, in the "Pipe Rolls of Devonshire", during the reign of King Henry 11, known as "The Builder of Churches", 1154 - 1189. 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.