“O God of Loveliness” is a beautiful traditional hymn, made even more so by these singing nuns. The hymn was written in the 18th century by St. Alphonsus Liguori. Liguori was not a hymnist by trade, rather the hymns attributed to him were compiled from his collected writings posthumously.
The hymn text was set to an 18th-century tune called “CRUSADERS’ HYMN.” Despite its name, there is no evidence that this melody dates back to the 12th-century crusades. It got this nickname after Franz Liszt used the tune for a crusaders’ march in his oratorio The Legend of St. Elizabeth (1862). For this reason, it is also sometimes called “ST. ELIZABETH.”