We like classical music. Our ring ceremony is outside with simple, elegant decorations. So I need a nice, beautiful song that fits with all of that. I think I would like instrumental only, but if you think there is a classical song with lyrics that would be nice go ahead and suggest it. It can be any length and my brother-in-law can loop it to fit the time allowed.

some nice ideas might be:

cantabile in b-flat major by chopin

claire de lune by claude debussy

lagrima by francisco tarrega

If your city has a symphony orchestra, contact them and see if any of their members have smaller groups that perform at weddings.

I got married in a large city. We hired a string trio from the symphony orchestra.

It was absolutely beautiful and the musicians were very professional! Friends were commenting how good the music was for quite some time!