Requiem aeternam dona eis Domine...
From the 'Lives of the Brethren of the Order of Preachers' (c.1260):
"Brother John Archer of Limoges, an eloquent and able preacher, appeared in great glory eight days after his death to a witness worthy of all credit and high attainments, who acquainted us with the fact and then proceeded to tell him how he had passed seven days in Purgatory for not having always been sufficiently grateful for benefits received, for being over fond of amusement, and for having pampered his body. On being requested to say what his sufferings were like, he declared that no earthly pains could be compared with them. When his interrogator ventured to ask him concerning his own conscience the brother replied: 'It has not been manifested to me, but if you persevere you will be saved. Learn besides that venial sins, of which men make so little in life, have to be otherwards bitterly expiated.' Lastly, when asked to explain the way in which he had been freed from Purgatory, he answered: 'The Lord sent his angels to bring me out, and they bore me up to him with sweet music and heavenly melodies, and the higher I mounted the more enchanting my delight became'."
Eternal rest grant unto them, O Lord and let perpetual light shine upon them. May the souls of all the Faithful Departed rest in peace. Amen.
The illustration above is taken from an 1898 Missale Romanum in my personal collection.