In the 17th century, a Vietnamese Buddhist monk converted to Catholicism and spent the rest of his life propogating the holy faith. This is a prayer that he wrote to be recited at funerals, death anniversaries, and the lunar new year.

According to one account, this monk (who was baptized with the name of Francis) was a high ranking Buddhist monk and a renowned member of the Tonkinese court. One day when the Jesuit Maiorica challenged the Buddhists monks of the court to a debate, Francis was so convinced of the verity of the faith that he asked to be catechized and converted, whereupon he labored to write catechisms and prayerbooks for the common people, as well as eloquent prayers such as this in Classical Chinese that earned him the esteem of the literati.

However, another story is that he was a Buddhist ascetic monk that was commanded by a Princess to keep watch over a certain pagoda for her since she believed that this pagoda would please the spirits and win her their favor. He was converted by Alexandre de Rhodes preaching and destroyed the idolatrous statues in the pagoda and converted it to a church. He then followed de Rhodes around inspiring many conversions, eventually leaving de Rhodes companionship to bring the Gospel to many more infidels. At the end of his life, sensing that his end was near, he made haste to return to his most beloved father, Alexandre de Rhodes and according to de Rhodes' account, the only thing that kept Francis alive on the long trip back was the hope of seeing his friends again. As soon as he arrived and saw de Rhodes, he dismounted his carriage, fell on his knees and, according to the story, died "like a second Simeon" in the arms of his father.

This prayer, written in Classical Chinese, was very dear to the North Vietnamese Catholics since it's creation. Stories tell of one Vietnamese martyr who during a famine would collect the corpses of the dead (touching the dead is a great taboo in Oriental culture) and sing this prayer while bringing their bodies to be buried.
 

This prayer is very beautiful and even non-Catholics admire its author's eloquence. Traditionally these petitions for the deceased included a lament at the deceased passing and praise for his achievements - this prayer however, laments the vanity of earthly life, and bemoans the utter misery of man and the complete mis-use of his earthly tenure to commit sin. It ends by imploring the mercy of God and the intercession of the Blessed Virgin and the Saints.