Giovanni Guerra was an Italian draughtsman and painter from Modena who worked in Rome, where he probably arrived in 1562, though he was not documented until 1583, when he frescoed three friezes of allegorical figures in the Palazzetto Cenci, a modest project for a patron who was not very prestigious.
For Cardinal Montalto he dedicated an elaborate composition of the Mystic Terrestrial Paradise, which he had engraved with verses composed for the occasion; decorations from the Sala Grande of the Palazzo alle Terme of the Villa Montalto are also attributed to Guerra: on 24 April 1585 the Cardinal was elected to the papacy as Sixtus V. In 1586 Guerra received the important commission, the first project of Sixtus, to fresco the staircase that connects the Sistine Chapel in the Vatican Palace with St. Peter's Basilica.