Personent hodie is a Christmas carol originally published in the 1582 Finnish song book Piae Cantiones, a volume of 74 Medieval songs with Latin texts collected by Jaakko Suomalainen, a Swedish Lutheran cleric, and published by T.P. Rutha. The song book had its origins in the libraries of cathedral song schools, whose repertory had strong links with medieval Prague, where clerical students from Finland and Sweden had studied for generations. A melody found in a 1360 manuscript from the nearby Bavarian city of Moosburg in Germany is highly similar, and it is from this manuscript that the song is usually dated.
The only reference to Bishop Thomas during his episcopate in Finland is a letter signed by him in Nousiainen in 1234, which granted certain lands around the parish to his chaplain, Wilhelm. The lands may be related to the papal permission from Pope Gregory IX in early 1229 that authorized the church to take over all non-Christian places of worship in Finland. The letter is the first surviving letter ever written in Finland.
No further information on bishop's activities has survived before he was granted resignation by Pope Innocent IV on February 21, 1245. According to the Pope, Thomas had admitted committing several felonies, like torturing a man to death and forging a papal letter. Church representatives to oversee the resignation were the Archbishop of Uppsala and the Dominicanprior of the Dacian province. Thomas donated his books to the newly established Dominican convent in Sigtuna and went on to live his last years in the Dominican convent in Visby, Gotland. He died there in 1248, shortly before the Second Swedish Crusade which cemented the Swedish rule in Finland for more than 550 years.