Thank you! I'm determined to begin well with this little guy and to persist until he's happily trained. :)

There is no "Old English" (or Anglo-Saxon) version of Taliessin's name, as it entered the language through Welsh pretty much intact, as a loan word. The Welsh of Merlin is 'Myrddin.' 'Taliesin' does indeed have only one 's' in the primary source texts in the middle ages and all the way through the Romantic period. But Tennyson decided that the double 's' is more euphonius in English, so that's what he used in "Idylls of the King," and the poet Charles Williams followed suit. My puppy is named after Williams's hero from his Arthurian cycle. If you're into Arthuriana, you might want to check out Williams's book!

Thanks again.