Watts's Nativity Carol

I sang this piece in high school, and I've been seeking it ever since. I believe that it's in the key of E, and the melody begins
Hush, my babe; lie still and slum-ber...
SOL ti RE RE ti RE DO DO

Any help? Thanks.

Eric Betthauser
Charlottesville, VA
ebettthauser@k12albemarle.org