The internet gives various origins to this surname. According to the Internet Surname Database, the surname Cass, Casse and in Dublin Cash is a group of surnames which derive from the female personal name Cass – a short form of Cassandra which was introduced into Britain around the time of the Crusades This was the name of an ill-fated Trojan prophetess of classical legend, who was condemned to foretell the future but never to be believed The name is also a metronymic in northern England and Scotland, which is so say that it derives from the mothers name, rather than the fathers.The website Forbears also gives the same definition and that it is the 23,900th most common surname in the world and there are approximately 21,503 people who bear this surname. The surname is most prevalent in the United States and the highest density is England .The origins of the surname according to Arthur, William in his book “An Etymological Dictionary of Family and Christian Names” published in 1857, the origin is “Gaelic.) Cas, a verb, to turn against, to thwart, oppose; a difficulty, a trying situation, a cause. Cas, a castle, the primary sense is to separate, drive off, or hate; the radical sense of hatred is driving off.”According to the British surname database, There are approximately 4,511people named Cass in the UK. That makes it the 2,333rd most common surname overall. Out of every million people in the UK, approximately 71 are named Cass.The earliest reference to the name in England is William Cass in the Essex county pipe rolls in 1200. Other recordings include Elyzabeth Casye, who married William Kendricke at St Dionis Backchurch, London, on August 27th 1564, whilst John Cass of Dalkeith, Scotland was summoned before the Privy Council for Scotland in 1566. The first recorded spelling of the family name is shown to be that of Roger Cass,
which was dated 1130, in the Registrum de Dunfermelyn, during the reign of King David 1st of Scotland”, 1124 – 1153.