The Church of the Assumption of the Buda Castle, more commonly known as the Matthias Church, more rarely the Coronation Church of Buda, is a Roman Catholic church located in the Holy Trinity Square, Budapest, Hungary, in front of the Fisherman's Bastion at the heart of Buda's Castle District. According to church tradition, it was originally built in Romanesque style in 1015, although few references exist. The current building was constructed in the florid late Gothic style in the second half of the 14th century and was extensively restored in the late 19th century. It was the second largest church of medieval Buda and the seventh largest church of the medieval Hungarian Kingdom.
It is a historic building with an important history. Two Kings of Hungary were crowned within its walls: Franz Joseph I of Hungary and Elisabeth, and Charles IV of Hungary and Zita of Bourbon-Parma.
The church was also the location of the "Mary-wonder." In 1686 during the siege of Buda city by the Holy League a wall of the church collapsed due to cannon fire. It turned out that an old votive Madonna statue was hidden behind the wall.