The decision to move the capital of the young Greek state to Athens in 1834 made it imperative to build a large new cathedral here. Construction started in 1839 and was completed in 1863. Since that time, this imposing building, decorated with fine murals and icons, has been Greece's most important church, used for official occasions. People wanting an insight into contemporary Greek culture and wishing to listen to splendid Byzantine music should attend Sunday mass which begins at 8a.