Henricus de Lettis
Born around 1188, it seems most likely that Heinrich or Henricus was educated at the same monastery as the first bishop of Livonia, Meinhard: the Augustine Monastery in Segeberg, Holsatia.
In 1205 latest he arrived in Riga, where he became a scholar of bishop Albert, and after having received the Holy Orders in 1208, he became a priest in Papendorf (Latvian: Rubene) at the river Ymera, where he still resided in 1259. The date of his death is unknown.
He was involved in the crusades especially against the Estonians around 1225, when he started to write down his "Chronicon Livoniae".