Work performed by slaves falls into five general categories: domestic, with epitaphs recording at least 55 different household jobs; imperial or public service; urban crafts and services; agriculture; and mining. Convicts provided much of the labour in the mines or quarries, where conditions were notoriously brutal. In practice, there was little division of labour between slave and free, and most workers were illiterate and without special skills. The greatest number of common labourers were employed in agriculture: in the Italian system of industrial farming "(latifundia)", these may have been mostly slaves, but throughout the Empire, slave farm labour was probably less important than other forms of dependent labour by people who were technically not enslaved.