Butrint, a UNESCO world heritage site constitutes a very rare combination of archaeology and nature. The property is a microcosm of Mediterranean history, with occupation dating from 50 000 BC, at its earliest evidence, up to the 19th century AD. In the 5th century AD Butrint became an Episcopal centre; it was fortified and substantial early Christian structures were built. After a period of abandonment, Butrint was reconstructed under Byzantine control in the 9th century. Butrint and its territory came Venetian control in the 14th century. At the beginning of the 19th century, a new fortress was added to the defensive system of Butrint built by Ali Pasha, an Albanian Ottoman ruler who controlled Butrint and the area until its final abandonment. The most interesting ancient Greek monument is the theatre which is fairly well preserved. The major ruin from the paleo-Christian era is the baptistery, an ancient Roman monument adapted to the cultural needs of Christianity. Its floor has a beautiful mosaic decoration.