This unusual surname is of early medieval Spanish origin, and is a patronymic form of the male given name "Domingo", itself deriving either from the Latin "Dominicus", belonging to the Lord, from "dominus", lord, master, or from "dies dominica", "day of the Lord". This name was borne by a Spanish saint, born of a Castilian family at Calaruega in 1170, who founded the Dominican order of monks. His subsequent fame gave an added boost to the popularity of the name, already well established because of its symbolic value. The characteristic Spanish patronymic suffix "-ez" is believed to derive from a Latin genitive "-ici" (denoting affiliation). Surnames derived from given names are the oldest and most pervasive surname type, and in religious naming traditions (as distinct from vernacular), names were originally bestowed in honour of biblical characters, saints, and cult figures. Recordings of the surname from Spanish Church Registers include: the birth of Fernando Dominguez at Jerez de la Fronterna, Cadiz, in 1544, and the marriage of Blas Dominguez to Catalina de Balbuena at Santa Maria Magdalena, Valladolid, on January 17th 1584. A Coat of Arms granted to the Dominguez family is a green shield with two golden towers joined at the middle by a black chain and surmounted by a black eagle. The first recorded spelling of the family name is shown to be that of Ambrosio Domingues, which was dated 1537, a christening witness at Chiclana, Cadiz, Spain, during the reign of King Charles 1 of Spain, 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.