Considering the chronological and financial limitations, as well as the state of the sources, the project aims to cover 5-10% of the population of Transylvania during the period studied (ca. 5.4 million births) thus providing 350-500.000 individual entries. The envisaged project duration is 36 months, but the working plan is structured so as to allow the subsequent continuous development of the database. Twelve micro-zones have been established as starting areas for data gathering. The micro-zones are scattered across Transylvania, covering various types of geographical areas (mountains, hills, valleys), historical regions (former border regiments, former Szekely sees and Romanian districts), and commercial and economic centers (market towns, railroad knots). The selected localities usually host two or more parishes of different denominations and ethnicity. The bulk of sources is formed by parish registers of various denominations. 1. Sources: Parish-registers (baptisms, betrothals, marriages, deaths, change in denomination, confirmations, blessings, vaccination). 2. Sampling units: The sampling is being made on geographical criteria, the basic sampling unit is the parish. 3. Variables used for selection: The main selection criterion is represented by the state of the sources: parishes with the best-preserved sets of registers go first, followed by the neighbouring parishes, in the same micro-zone, whit less preserved sources. 4. Selection method: Twelve micro-zones have been established as starting areas for data gathering according to our own methodology. The micro-zones are scattered across Transylvania, covering various types of geographical areas (mountains, hills, valleys), historical regions (former border regiments, former Szekely sees and Romanian districts), and commercial and economic centers (market towns, railroad knots). The selected localities usually host two or more parishes of different denominations and ethnicity. The bulk of sources is formed by parish registers of various denominations. The selected localities are going to be entirely included in the database.