Bran Castle has a six-century-long history as a fortress and royal residence. Its function has changed several times - originally it was a fortress, then it became a customs house and local administration office, and later, in the first half of the twentieth century, a royal residence. The castle is built on a rock at the narrowest point of the Turcu River valley. The fortress has a trapezoidal perimeter, and on the north-east side its outline is determined by the rock on which it lies. The castle was built very quickly, in about 4 years. The materials used were stones from the river, bricks, and, in the upper and interior parts, wood.

A radical change in the function of the castle and its decoration took place in 1921 when Queen Maria of Romania established her summer residence there. The royal court architect Carol Liman changed the function of a lot of spaces. Beautiful wall paintings by a famous Romanian painter, Arthur Verona, covered the interior of the castle's chapel.

The Bran Castle Museum is not a 'typical' museum, since it is located in the countryside, and it has no heating system, no air-conditioning, and only a few showcases. The castle's collection contains various art objects and historical documents displayed in different buildings of the museum complex. Among these documents there are some which testify to the importance of Bran Castle in the political and economic life of the area. The inappropriate lighting has affected the paper and leather objects through fading processes.

Monitoring of temperature and humidity, as well as concentrations of sulphur dioxide (SO2), nitrogen dioxide (NO2), ozone (O3), and acetic acid (CH3COOH) was carried out for more than 12 months. The study will give a scientific basis for the selection of an appropriate heating system. As the outdoor climate affects the indoor situation, the environment in the museum is characterised by a high intrusion of pollutants. The large number of visitors contributes to a rise in humidity inside the museum. In consequence, high biological contamination has been detected on wood objects, the walls and the frescoes. Part of the collection is not exhibited because conservators can not create safe conditions for the objects.

Bran Castle is a museum of high national importance, visited by increasing numbers of visitors. The results of our project will be further used to assess the situation in several other historic buildings in the region.