Saint George's Church was probably founded in 1251. The date was proposed based on an Arabic inscription on a khachkar over the western door of the church yard. According to 13th century chronicler Hovhannes Erznkatsi, the church was built by Prince Umek of Karin.
The church was given to the Persian garrison by Safavid Shah Abbas I of Persia in 1616 and returned to the Armenian community in 1748 by King Heraclius II of Georgia. It was burnt when Persians sacked Tbilisi in 1795. The church was thoroughly restored in the 17th century, and then again in 1832 and 1881.
It became the seat of the Georgian Diocese of the Armenian Apostolic Church after the Vank Cathedral was demolished by Soviet authorities in the 1930s.
The most recent renovation of the church began in 2012 and was completed in 2015.
The church is built on a traditional plan of a partitioned, open cross with a rectangular perimeter. Like most of the churches in Tbilisi, it is built in brick. The outer walls of the church are covered with stucco.
Late 18th-century paintings by Hovnatan Hovnatanian decorate the church's interior. Between 1922 and 1923 Gevorg Bashinjaghian decorated the church's internal walls, the altar, and the walls in front of it, creating four large murals.
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.