Recorded in the spelling forms of Aguilar, Aguilera, and Aguiar, this surname is usually Spanish, but may also be Portuguese and Ashkenasic. It is habitational, and describes a person who originally came from a place known as 'the eagles lair', being a developed spelling of the Roman (Latin) 'aquilaria'. From about the year 100 a.d. until the collapse of the Empire in the year 410 a.d., Spain was merely a province of Rome. The influence of the Romans was profound, and many present day Iberian surnames owe their roots to the Roman influence. The surname itself is much later, few surnames except those where the holder was associated with specific estates, were hereditary, although this was one of them. Early surname recordings include such examples as Flores Aguilar of Santa Ana, Mexico, on July 21st 1778, and Jose Aguilar of the San Diego Mission, California, who married Maria Lopez on December 6th 1781. The coat of arms granted in Spain has the very distinctive blazon of a gold field, charged with a black eagle displayed. The first recorded spelling of the family name is shown to be that of Luis Aguilar, which was dated August 24th 1661, in the registers of the city of Asuncion, Mexico, during the reign of King Philip 1V of Spain and Emperor of Mexico, 1619 - 1665. 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.