At the time of Zand dynasty, it was a small town that was significant from a military point of view. The first of the Qajar kings, Agha Mohammed Khan, named Tehran as the country's capital in 1778. Nevertheless, the capital's development started at the time of another Qajar monarch, Fath-Ali Shah. The citadel, which Agha Mohammed Khan had built, was developed to include the new royal buildings.
At the same time, the city's population was redoubled. With the increasing importance of the city, soon gates, squares and mosques were built and it was at the time of Nassereddin Shah that the city's master plan was prepared and modern streets were formed. Later, large central squares like Toopkhaneh (now Imam Khomeini) square and several military buildings were constructed. With the decline of the Qajar dynasty, Tehran soon took the shape of a modern city. The construction of large government buildings, new streets, recreation centers, urban service establishments and academic and scientific centers were started, while most of the old gates and buildings were destroyed and the city's old architectural fabric replaced by a modern one.