There is very little reliable evidence bearing upon formal education in the early period. Education was then certainly centred on the family and was probably based upon apprenticeship supervised by the father—in poorer homes an apprenticeship to agriculture or trade, in more aristocratic circles to military service and public life (what later became known as the tirocinium militiae and the tirocinium fori). The authority of the father, legalized as *patria potestas, was absolute and could only in theory be questioned by the censors. The Roman mother had a more restricted, domestic role but she too was traditionally expected to take a personal, central responsibility and to set a strong moral example (see motherhood, Roman). It is not certain when reading and writing became a serious part of Roman education: the 7th-cent. bce ivory writing-tablet with inscribed alphabet found at Marsiliana d'Albegna and 6th-cent. bucchero (pottery) models of wooden writing-tablets (tabulae ansatae) from Etruria may imply that *literacy was then already making some headway.