Thank you all for your swift and helpful answers. Now I need to make the syllables fit in modern English for the second time round. It isn't easy as, for example, 'sancte bonifati' has 6 syllables and 'Saint Boniface' has only 4. They don't correspond so it means stretching the words differently over the melismata and my initial attempts soon run into trouble. I'll have to give this some thought.

Thank you all for being so helpful.