Abstract
The Sri Lanka National Archives (SLNA) in Colombo preserve under the names of head thombo and land thombo several hundreds of eighteenth-century registers on family composition and landownership. At the time of their compilation by the Dutch East India Company or VOC the thombos suited a general administrative purpose; currently they are used only in genealogical research and in court cases concerning land disputes. Demographic, family and colonial history, however, can profit considerably from this neglected source. In the following we describe a project to digitize the registers of the Colombo province, and we discuss and evaluate the variables in the database by focusing on the family groups of a relatively small district.