Possibly a Spanish form of the Late Latin name
Sanctius, which was derived from the word
sanctus meaning "saintly, holy". Alternatively,
Sancho and
Sanctius may be derived from an older Iberian name. This was the name of a 9th-century saint who was martyred by the Moors at Cordoba. It was also borne by several Spanish and Portuguese kings. Miguel de Cervantes used it in his novel 'Don Quixote' (1605), where it belongs to the squire of Don Quixote.