This famous Italian and Spanish surname has Roman pre Christian origins. Recorded in no less than eighty forms ranging from Casa, Caso, Dell Casa, Casillis, Dalla, and Dacca, to Cassella, Casetti, Cason and Casaccio, this is a residential surname for one who lived in a manor house or at least the most distinguished dwelling in the relevant town or village. The surname also has aristocratic nameholders, the Counts of Casillis being members of the Spanish nobility. Residential surnames may as in this case, relate to holders of estates, although more usually they are 'reference' names, being granted to them by their neighbours, when they moved from their original village or homestead to another area. To call somebody by the name of their former home being one of the easiest means of identification. The following recordings have been taken from ancient civil and religious registers. They include Hernando de la Casas of San Estaban, Vizacaya, Spain, on February 9th 1573, Magdalena Casa of Olot, Gerona, Spain, on November 27th 1666, Guillermo Casillo at St Catarina, Districto Federal, Mexico, on February 11th 1759, Maria Marcela Casillis at St Cruz Y Soledad, Mexico, on January 17th 1786, Valentino Caso of Caserta, Italy, on september 19th 1848, and Antonio Robes Casillas, at Los Angeles, California, on January 28th 1908. The coat of arms has the blazon of a silver field, a red chevron between three red cross-crosslets, inside a red border. The first recorded spelling of the family name is shown to be that of Quitteria Casas, which was dated February 19th 1524, at Medina, Gerona, Spain, during the reign of King Phillip 1st of Spain, Emperor of Mexico, 1516 - 1556. 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.