Jakob Erlandsen (died February 18, 1274) was a Danish Archbishop of Lund (1254–1274) and the central character of the first great church conflict in Denmark.
Belonging to a wealthy magnate family (Galen clan) that was related to Archbishop Absalon Erlandsen and all others of Hvide clan, he became a clergyman. He was educated in Paris and showed a solid juridical knowledge at visits in Rome. From the start he seems to have represented a stand of opposition towards the royal power and as bishop of Roskilde (from 1250) he was at odds with King Eric IV. His zeal seems to have been a de facto independence of the church in relation to the king and the state power. In many ways this was in accordance with international canonical law and in agreement with the offensive course of the papal policy but in Denmark it was relatively unknown; here king and bishops normally had worked together, the latter recognising the upper hand of the king.
1254 bishop Jakob was appointed archbishop and by this his real struggle with the king began. King Christopher I strongly resisted the archbishop’s wish of adjusting the legislation and juridical right of the Danish church with international canonical law because it meant a severe hampering of the state power, among other things of its financial energy. Furthermore, this might very well make the archbishop the independent ruler of his diocese Scania. After many minor conflicts archbishop Jakob 1256 issued the so-called Vejle Constitution, a law that was meant to secure all bishops against any kind of arrest from the king’s side by threatening him with an interdict. This law was an open challenge to the king and was far from being supported by all bishops. During the next years Jakob Erlandsen and King Christopher more and more came on collision course and when the archbishop in a critical situation refused to accept the king’s son Eric (Eric V) as crown prince he was arrested and imprisoned 1259.