Already in the 12th century a church was built at this site. It was the most important church in Prague's Old Town until the constructuon of the Týn Church
The current St. Nicholas church at Old Town, designed by Kilian Ignaz Dientzenhofer, was completed in 1735. It wasn't until 1901, when the Krenn House was demolished that the Baroque façade was visible from the older square. The white façade is decorated with sculptures made by Antonín Braun.
The marvelous interior of the church is inspired by the chapel of St. Louis-des-invalides in Paris. The delicate stucco decoration was executed by Bernardo Spinetti, the frescos were made by Peter Adam the Elder.

In 1781, after emperor Jozef II ordoned the closure of all monasteries without a social function, all decoration in the church was removed. From 1870 to 1914, the church was used by the Russian orthodox congregation.
During the second World War, Czech army units were stationed in the church. Artists, who otherwise would have had to go to the front, were set to work by a colonel to restore the church. After the war, the church was handed over to the Czech Hussite movement.

Note that besides this Church at the Old Town Square, there is another Saint Nicholas Church in Prague, but in Lesser Town across the Vltava river.