Established in 1741 by King Charles III of Bourbon, the Catasti Onciari were real censuses carried out for fiscal purposes. They are documents of primary importance in the reconstruction of the genealogical tree of a family as they represent a valuable source of information not only on its socio-economic status but also on its composition. For each family, in addition to the description and value of the assets owned, the name of the head of the family, the age and place of birth, and sometimes the indication of paternity and maternity are reported; also names and ages of the wife, children and any related and non-related cohabitants (servants and various personnel). In Sicily the equivalent of the Catasti Onciari is represented by the "Riveli of goods and souls", compiled by every municipal administration on behalf of the “Magna Curia dei Maestri Razionali” (since 1569 Court of the Royal Patrimony) which was the supreme body of control and jurisdiction in financial matters. In 1682 the jurisdiction of the Court passed to the Deputation of the Kingdom. The numerous registers concern almost all the Sicilian municipalities and cover the period between the sixteenth and eighteenth centuries: the Riveli drawn up in the years 1548, 1569, 1584, 1593, 1607, 1616, 1623, 1636, 1651, 1682, 1714 and 1748 are preserved. The Riveli of goods and souls are therefore an irreplaceable source of research to supplement that carried out in the parish archives but also in its replacement, when the parish archives are very incomplete or even no longer existing or inconsultable.