Difficult text, much of it in dialect--luckily, translated into Italian on facing page. I read several one-acts when I first bought it in Milano, but recently reviewed more.
"Mistero" recalls medieval Mystery plays (like those from York) staged outside churches. DF has several featuring the marriage at Cana, the graveyard Lazarus resurrected from--where the gravetender charges entry fees since visitors wreck stones and shrubs. Finally, scenes of Christ on the cross, a Madman at the foot, thieves on adjacent crosses, various Marias (has a ring to it), no nefarious Maries.
In "Maria alla Croce," Christ from the cross talks to his mother, who has criticized Gabriel for deluding her promising she would be a Queen, not a Queen whose son has nails in his feet. Christ tells her to go home, because he must die, but he can't with her near. Begging the soldiers to let her wash the blood from her son's feet, she swoons and criticizes Gabriel for his beautiful multi-colored feathery wings, seducing her for God's purposes, putting her through this hellish loss. Her son had urged her not to blaspheme. (160-170)
Recently I was astounded to read about a Good Friday orgy in 1301, under "Bonifacio VIII," whom Dante knew--and put in Hell. Dante says, "Ah Bonifax, you have betrayed the Church like a whore!" Earlier, Bonifacio , on an embassy to England with a Visconti (also a future Pope) was only released from the Tower of London by Edward I. One Fra' Dolcino had taught peasants they had a right to the food they grew, and the land they grew it on. (This, near Lago Maggiore, half of Lombardy and half of the Piedmont.) A Visconti duke descended with troops, bound peasants hand and foot, carried them to prison.
In protest on Good Friday, Fra' Dolcino, a sympathizer with the proto-"protestant" Catari, said, "Christ was a poor man, without a coat, shoeless…and here the Pope wears fancy robes and jewels, sits on a throne of gold" (Bon VIII did enrich himself and his office). Fra' Dolcino organized (if that's the word) prostitutes, "men of good family" (!), dressed up as bishops and even Cardinals, paraded through the streets of Rome, with entertainment such as extinguishing a candle three meters away with..a burp! The Good Friday orgy scandalized even the grosser kings of Europe. (pp 106-111)
To end where Fo begins, Quattrocento performances on platforms erected, staging, before churches, say, at Antwerp: From the stage, "Christ or Barrabas, who do you want on the cross?" The crowd yells, "JEAN Gloughert!"(the mayor of Antwerp). Maybe we should forbid? the mayor's friends think. In Paris, at the Place de Louvre, an actor plays Christ on stage, Jewish elders wear Bisahops' mitres. The bishops defend the landowners against the people: casting the bishops, the director looks for faces of thieves! (p.21) So, of course the bishops forbid, an even execute one German jester still performing folk plays; Hans Holden is burned alive. He thought the bishops would themselves laugh, but bishops don't laugh. ( )

http://www.ilpotereelagloria.com/libri/Dario-Fo-Mistero-buffo ( )