Sibiu was colonized by Saxon settlers in the mid-12th century. They were invited to Transylvania by the Hungarian King Geza II (1141-1162), in order to defend and administer the kingdom's border territory. The earliest written records date from 1191. From 1366 onwards the city became known by the Saxon community as Hermannstadt. Although Sibiu is an ancient settlement dating from the Neolithic period, the overall form and shape of the city is medieval. Its evolving lines of strong fortifications, together with its characteristic street pattern, squares and building plots, developed and grew especially following the Tatar invasion of 124-1. Sibiu was the capital of the Saxon settlement in Transylvania. Strategically located, it was its most important fortified town. It was also its administrative, religious and economic centre. At the end of the 15th century the Saxon University was founded, with the leadership based in Sibiu, and from 1543 it became the focus for the introduction of the Lutheran Reformation into Transylvania and the shift away from Catholicism. The plan form and the architecture of Sibiu bear witness to the important political, religious and economic role that the city played for almost six centuries. Of particular note are the three interlocking squares of the upper town (Huet, Kleiner Ring, Grosser Ring), the succession of smaller squares in the lower town (including Fingerlinger and Dragoner), and the many narrow streets, steps and covered passages that link them. The historic centre displays an extensive stock of Gothic, Renaissance, and Baroque architecture, as well as examples of late 19th to early 20th century date. Amongst its key buildings are: St. Mary's Parish Church, c. 1350; the Altenberger Haus (the old City Hall), 1475-1704; and the Brukenthal Palace, 1778-1788. The plot shapes, layout and organization of the larger merchants' houses in the upper town, with their large courtyards behind, are also distinctive. The evolution of the city from its initial strategic stronghold protecting a rural settlement to a mercantile and artisan centre and powerful regional capital city is expressed in the important collection of vernacular buildings, to be seen especially in the lower town. The historic centre of Sibiu covers an area of approx. 80 ha. It comprises the whole of the area within the fourth ring of fortification and is situated at the heart of the modern city. .