John Canaparius (German: Johannes Canaparius) was a Benedictine monk at the Aventine monastery in Rome. It had long been assumed that in the year 999 he wrote the first Vita sancti Adalberti episcopi Pragensis, or "Life of St. Adalbert of Prague" just two years after Adalbert's death.
Adalbert was sent by Pope Gregory V to convert the pagan Old Prussians to Christianity and had come to Prussia, apparently taking the route along the Vistula River to reach the Baltic Sea at „urbem Gyddanzyc“., which is identified with the later Gdańsk (Danzig). Then a small trading and fishing settlement with wooden buildings, it was anyway recorded by Canaparius as „urbs“, city.
It is, however, now assumed by Johannes Fried, that the 'Vita' was not written by Canaparius, but was written down in Liège, with the oldest traceable version having been at the imperial Adalbert shrine at Aachen. It was only recently recovered at the Marienstift, and is used to reconstruct the archetype of the 'Vita'. Bishop Notger of Liège, a hagiographer himself, apparently had knowledge of the earlier handwritten Vita from Aachen. The imperial court at Aachen had in 997 assembled immediately upon receiving word of Adalbert's death and had thereupon planning the upcoming events.
Another famous biographer of Adalbert was St. Bruno of Querfurt who wrote his hagiography in 1001-1004.
Nikolaus von Jeroschin translated the Vita Sancti Adalberti into Middle High German in the 14th century.