The cornerstone of the Metropolitan Cathedral was laid in December 1842 by King Otto and Queen Amalia. Theophil Hansen, the Danish architect who designed the Academy of Athens and the National Library, also made the first plans for the cathedral. However, due to a lack of funds, the construction was on hold from 1843 until 1846. Eventually, the amount was raised thanks to personal donations made by King Otto and the benefactor Georgios Sinas, fund-raising activities, and sales of ecclesiastical properties.
When the project resumed in 1846, the basilica started being built according to the designs of Dimitrios Zezos. After he died in 1857, French architect Francois Boulanger and Greek architect Panagis Kalkos supervised the project.
The construction was completed on May 21, 1862, and the church was dedicated to the Annunciation of the Virgin Mary
