Short answers, pulled from the story.
Giovanni Pierluigi da Palestrina was an Italian composer of late Renaissance music, born in the town of Palestrina in the Papal States between the 3rd of February 1525 and the 2nd of February 1526. He was the central representative of the Roman School and is considered the leading composer of late 16th-century Europe.
Palestrina is primarily known for his masses and motets, which number over 105 and more than 300 respectively. He also wrote 68 offertories, at least 140 madrigals, 35 magnificats, 11 litanies, more than 70 hymns, and a cycle of lamentations.
No. The story that Palestrina composed the Missa Papae Marcelli to persuade the Council of Trent against banning polyphony is false. The mass was composed before the cardinals discussed any ban, possibly ten years before, and the Council of Trent never officially banned any church music.
The Palestrina style is a method of Renaissance counterpoint based largely on the codification by 18th-century theorist Johann Joseph Fux in his 1725 work Gradus ad Parnassum. Fux divided counterpoint into five species and cited Palestrina as his model, relegating dissonances to suspensions, passing notes, and weak beats.
Palestrina died in Rome of pleurisy on the 2nd of February 1594. He was buried the same day beneath the floor of St. Peter's Basilica in a plain coffin bearing a lead plate inscribed Ioannes Petrus Aloysius Praenestinus Musicae Princeps, and his grave has never been located.
Palestrina left his post as maestro di cappella of the Cappella Giulia in 1555 because Pope Paul IV ordered that all papal choristers be clerical. Having married early and fathered four children, Palestrina could not continue as a layman.