I had been hearing the bagpipes a couple of streets away, then fortunately found the source.
Bagad Kadoudal had traveled across the channel to join in the parade. Now they were about to give an impromptu performance.
A crowd had been drawn into the little park by the church, where we watched them warm up. Visitors to the city, in a variety of accents, openly asked questions. Just as openly, the watching Welsh answered them. It felt special to be there.
The Breton players were finally ready, bagpipers, pipers and drummers fell into formation. In typical Celtic fashion, as soon as we heard the music, we followed. They only took us around the corner, then congregated around the Owain Glyndŵr pub to lead with a series of reels.
I couldn't help my feet moving. Neither could a Welsh lady across the circle. Without any prior planning, we were dancing together with the musicians nodding in smiling encouragement. It wasn't long before we were teaching tourists how to move their feet in the Celtic style.
More and more people joined in, including Breton men and women, who'd arrived with the band. I didn't know that there was a difference between Welsh and Breton traditional dancing. The styles are obviously related, but in Brittany it's a little more understated. We ended up with a fusion of the two.
Those not dancing helped keep the time with clapping and stamping their feet. It was quite a crowd that gathered there!
I was struck by the gathering of the Celtic tribes here too. Welsh and Breton danced together, before a public house dedicated to the greatest of Welsh heroes, on St David's Day too. But two doors away was the Cornish pasty shop; and beyond that O'Neill's Irish bar.
All that was missing were the Basque, Manx and Scots. The latter turned up towards the end - two men in Highland plaid, talking in broad Glaswegian accents - cheering as they saw what must have looked like a spontaneous céilidh.