Composed around 1706 but never performed during Eccles’ lifetime, Semele sits at a crossroads in musical evolution. Just as the English suspicion for the “effeminate” delights of opera were waning and the compromise of semi-opera was finally giving way to through-sung works, the fragile new tradition was knocked aside by the young Handel whose Rinaldo took London by storm, making Italian opera, not English, the pinnacle of fashionable entertainment.

History is written by the victors, and it wasn’t until the 1960s that Eccles’ opera finally emerged from Handel’s shadow and made its stage debut. A recording by Florida State University Opera and...