Laudes regiæ
The laudes regiæ are a hymn used in the Latin Rite of the Catholic Church. There are variant texts, but they most often have the incipit that gives the hymn its alternative title: Christus vincit, Christus regnat, Christus imperat. Formularies of the laudes regiæ praising the Holy Roman Emperor are referred to more specifically as the laudes imperiales.
The melody of the refrain is also used as an interval signal for Vatican Radio's shortwave transmissions.
History
This hymn is sung in the Catholic Church at solemn events, such as the inauguration of a pope or, in centuries past, the coronation of the Holy Roman Emperor. It is also sung at processions, such as those held on the feasts of Corpus Christi and Christ the King.The laudes regiæ has origins as far back as Ancient Rome: when leaders such as generals, emperors or consuls entered the City of Rome for a triumph after winning a battle, they were met with the chants from the people. Charlemagne later adopted such Roman traditions: when crowned Emperor of the Romans by Pope Leo III in Old St. Peter's Basilica on Christmas Day 800 A.D., laudes were sung during the coronation ceremony – possibly already including the formula "Christus vincit, Christus regnat, Christus imperat".