This interesting and unusual surname has two possible origins. The first is that it is a metronymic (of the mother) form of "Cassandra", a popular medieval female given name. This was the name of an ill-fated Trojan prophetess of classical legend, condemned to foretell the future but never be believed; her story was well known in England during the Middle Ages. Alternatively, it may be a dialectal variant of a locational name from a place called Cawston in Norfolk and Warwickshire. The derivation is from the Old Scandinavian pre 7th Century personal name "Kalf", and "tun" a settlement, thus "Kalfstun", and is recorded in the Domesday Book of 1086 as "Caustuna", and "Caluestone". Locational surnames were developed when former inhabitants of a place moved to another area, usually to seek work, and were best identified by the name of their birthplace. The early loss of the "I" is due to the Norman influence after the Invasion of 1066. On April 4th 1659, one Blythe Casson married Thomas Wayturne at All Saints, Norwich, Norfolk. The first recorded spelling of the family name is shown to be that of John Casse, which was dated 1170, in the "Pipe Rolls of Yorkshire", 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.