The Erechtheion is an ancient Greek temple on the north side of the Acropolis of Athens which was dedicated to both Athena and Poseidon.
The temple as seen today was built between 421 and 406 BCE. It may have been built in honor of the legendary king Erechtheus, who is said to have been buried nearby. Erechtheus was mentioned in Homer's Iliad as a great king and ruler of Athens during the Archaic Period, and Erechtheus and the hero Erichthonius were often syncretized. It is believed to have been a replacement for the Peisistratid temple of Athena Polias destroyed by the Persians in 480 BC.
The Erechtheion underwent extensive repairs and reformation for the first time during the 1st century B.C., after its catastrophic burning by the Roman general Sulla. The intact Erechtheum was extensively described by the Roman geographer Pausanias, writing a century after it had been restored in the 1st century AD. The building was altered decisively during the early Byzantine period, when it was transformed into a church dedicated to the Theometor. With this alteration many architectural features of the ancient construction were lost, so that our knowledge of the interior arrangement of the building is limited. It became a palace under Frankish rule and the residence of the Turkish commander's harem in the Ottoman period.
In 1800 one of the caryatids and the north column of the east porch together with the overlying section of the entablature were removed by Lord Elgin in order to decorate his Scottish mansion, and were later sold to the British Museum (along with the pedimental and frieze sculpture taken from the Parthenon). During the Greek War of Independence the building was bombarded by the Ottomans and severely damaged, the ceiling of the north porch was blown up and a large section of the lateral walls of the cella was dismantled. The Erechtheum went through a period of restoration from 1977 to 1988.
References:The Petersberg Citadel is one of the largest extant early-modern citadels in Europe and covers the whole north-western part of the Erfurt city centre. It was built after 1665 on Petersberg hill and was in military use until 1963. It dates from a time when Erfurt was ruled by the Electors of Mainz and is a unique example of the European style of fortress construction. Beneath the citadel is an underground maze of passageways that can be visited on guided tours organised by Erfurt Tourist Office.
The citadel was originally built on the site of a medieval Benedictine Monastery and the earliest parts of the complex date from the 12th century. Erfurt has also been ruled by Sweden, Prussia, Napoleon, the German Empire, the Nazis, and post-World War II Soviet occupying forces, and it was part of the German Democratic Republic (East Germany). All of these regimes used Petersberg Citadel and had an influence on its development. The baroque fortress was in military use until 1963. Since German reunification in 1990, the citadel has undergone significant restoration and it is now open to the public as a historic site.