Fairest Lord Jesus written as Schönster Herr Jesu by German Jesuits, published in 1677; English version by Seiss, 1973. Music a Silesian folk song, pub. 1842, arr. Willis, 1850.
Cyberhymnal: Fair Lord Jesus

Little is known of the church music of the time. Joe Offer has commented on a couple, but I have forgotton the names and threads.