Laudes Regiae is a processional hymn. In other words it's to be found in a book for use by the Church (Western Christianity rather than Orthodox or African) that collects in one place all the texts used in a liturgical procession such as chants and rubrics. These books first started to be written in the 10th century and the started to become widespread by the 11th century. They're of great musical interest because the contain material not found in other books.
This particular processional dates from before the Norman conquest of England. It was originally sung by the Benedictine monks of Fécamp Abbey (Abbaye de la Trinité de Fécamp), a manuscript Osmund containing it was brought to Old Sarum by Osmond, bishop of Salisbur (died 1079 A.D.) to Old Sarum from whence it found its way into an eleventh-century manuscript in Salisbury Cathedral Library. The idea behind Advent processionals which always started in the Western side of the church, abbey, or cathedral in which they took place was to symbolise the Church journeying from the West to the Holy Land, there to await the birth of the Christ-child.
The version you can hear in the music video below is a modern edition based on the original and prepared by Christopher Dearnley for use by the Choir of St. Paul's Cathedral, London, for use during an Advent processional, the cantor is Timothy Jones and the choir is the Choir of St. Paul's Cathedral, London. The video, Latin lyrics, and a translation into English are all below the fold. Enjoy :-).
|Christus vincit, Christus regnat, Christus imperat.|
Exaudi, Christe, ecclesiae sanctae Dei,
supra regnorum fines nectenti animas:
Rex regum. Rex noster. Spes nostra. Gloria nostra.
Christ conquers, Christ reigns, Christ rules.
uniting souls across the divisions of nations:
King of kings. Our king. Our hope. Our glory.