This unusual Spanish-Italian surname is either topographical or a nickname. If the former it derives from the Roman (Latin) 'cirrus' meaning bristle or spine, and describes a person who lived on a steep hill or ridge. If the latter then the original is much the same except that the 'bristle' is believed to refer to a person with spiky or a tuft of hair! Medieval humour was extremely 'basic', and many early surnames would today be regarded as at best offensive and probably obscene in translation. Spanish surnames are often heavily influenced by Latin origins, the Iberian countries of Spain and Portugal being for several centuries part of the Roman Empire, the same names are often found in both Italy and the Iberian peninsula. This surname is no exception, it being recorded in the forms Cerro, Cerio, Cerri, and Cerra, and the Spanish diminutive 'Cerillo' - 'Little Cerro'. Examples of the surname recording include Santiago de Cerillo, who married Maria Santos de la Rivas, at San Estaban, province of Vizcaya, on Novmber 28th 1658, Angel Cerro, who married Maria Cruz Berjas on November 25th 1802 at Arrabal de Portillo, province of Valladolid, and Maria Josepha Cerro who married Asencio Carretero at San Lorenzo Martir, Albacete, Spain, on April 13th 1830. The coat of arms has an oak tree in full bloom on a silver field. The first recorded spelling of the family name is shown to be that of Maddelena Cerri, which was dated March 30th 1586, christened at Tassignano, Lucca, Italy, during the reign of Pope Sixtus V, who reigned from 1585 to 1590. 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.