Misteri Play d’Elx

The d'Elx Mysteri Play, about the Blessed Virgin's Assumption was performed on Radio 3, on Saturday "they called it Elche", listen.
When the Council of Trent forbade such spectacles in Church, the local citizenry petitioned the Pope for an exemption, and the play has been performed in the Cathedral ever since.
Everything is sung, so it is really a very early opera, all the players are men or boys and sing monody and ployphony in an extra-ordinary open throated way, some of the parts of this play go back to the 13th Century. Look at this site which is translated by machine unfortunately, but is fascinating.