If it was really Latin that you saw, then it might have been:
Surge aut sis eques in nomine Dei 1
Stand up as a knight, in the name of God.
This is how William Camden described the ancient ceremony in his Britannia. There are variations, such as substituting vel
for aut
. I'd be a bit surprised if the site you originally found actually used Latin, though.
Since you expected to find the answer in English ("I dub thee"), I suppose the question is focused on England. In that case, as @SteveBird's rightly points out, the traditional words are in French, not Latin. Complementing his answer, the classical formula is for the sovereign to lay a naked blade on the candidate's left shoulder and pronounce:
Sois chevalier, au nom de Dieu 2
(Be thou a knight in the name of God)
Followed by the command to rise:
Avancez chevalier 2
(Arise, knight)
The use of French has long since died out in English governance. In later times, it appears the monarch simply pronounce:
Rise up, Sir (name) 3
This part is possibly slightly profane. Mouseover to show.
Jake Cade: Rise up, Sir Dick Butcher
- William Shakespeare, 3 Henry VI (certain versions).
Sources:
[1] Jacob, Giles, and Thomas Edlyne Tomlins. The Law-Dictionary: Explaining the Rise, Progress, and Present State, of the English Law. A. Strahan, Law Printer to the King's Most Excellent Majesty, 1809.
[2] Burke, John Bernard. The Knightage of Great Britain and Ireland. London: Edward Churton, 1841.
[3] Cox, Thomas, and William Camden. Magna Britannia et Hibernia, Antiqua & Nova Or, A New Survey of Great Britain. Savoy: Nutt and Morphew, 1720.