Recorded in many spelling forms including Maestro, Mastro, Magistro, Marro, and with patronymics and diminutive suffix such as -ello, -ini, and -aro, this is an Italian surname. It is pre medieval in origin, and describes a "master". This was a guild master, one who was at the very top of his trade or profession. The title was often used as prefix to their baptismal names to give examples such as Mastronardi or Mastrovalerio. To add to the confusion, many, indeed the majority of Italian surnames did not become heriditary in a "locked" spelling sense as understood in other countries such as Britain France and Germany, until the 19th century, and the creation of the modern Italian state. This began in 1860 when Garibaldi marched upon Rome and demanded that the existing twelve separate kingdoms and principalities formed an integrated federation. In the past most of the individual states were financially poor and paid little attention to keeping records, thus making it very difficult to research Italian surnames except those of some of the nobility, in a genealogical sense.