The Cathedral Basilica of the Assumption (or Pelplin Abbey) is a former Cistercian abbey, located in Pelplin, Poland, to the south of Gdansk. It was founded in 1258 by Sambor II, Duke of Pomerania, as "Samboria". Work on the Brick Gothic building (length 80 m, height 26 m) began in 1289. The church was finished in 1323.
Next to the cathedral there are former monastic buildings, in which now is located the theological seminary.