Further, he prohibited the custom of self-imposed thraldom. The only act of Birger’s which has been condemned was his attempt to introduce feudalism. His second son, Magnus, was created a duke, and received, at Birger’s death, Sœdermanland, with the castle of Nykœping as a duchy. This gave rise to much strife and many conflicts within the new royal branch of the Folkungs, and endangered the unity of the kingdom. Birger, the last jarl of the realm, was the first real statesman of Sweden, whose stern intellect and integrity of character won for his country an honored position among its neighbors, and for himself the admiration of many generations to come. He died in 1266. The first few years after Birger’s death were peaceful. The archbishop’s seat was removed to the present Upsala, where work was commenced on the magnificent cathedral. In 1271 the commercial privileges held by Lubeck and Hamburg were also granted to Riga. Valdemar was a weak and frivolous man, and his licentiousness gave his brother Magnus the idea of pushing him aside, and later deprived him of the loyalty and respect of his people. The difficulties with his brothers ended in open conflict; Magnus and his younger brother Eric turned to Denmark and Germany, where they hired an army, King Eric Glipping of Denmark helping them with troops on promise of good securities. The brothers invaded West Gothland and defeated a Swedish army at Hofva, in 1275, while the king with his best troops remained inactive at Tiveden. Valdemar fled to Norway, bringing his son Eric with him. Venturing back into Vermland, he was captured and brought before Duke Magnus. Valdemar went so far as to abdicate his throne, but the meeting ended in an agreement according to which _Magnus_ was to become king of Svealand and Valdemar to keep Gothaland. Eric was made a duke, but died in the same year. Magnus was crowned at Upsala in 1276. King Valdemar did not long remain content with the new state of things. One month after Magnus’s coronation he arranged a meeting with him at Lœdœse, over which King Magnus Lagabœte of Norway presided, but without being able to effect an agreement between the brothers. Valdemar now turned to King Eric of Denmark, and won an ally in him because Magnus had neglected to fulfil his promises. Magnus gained a supporter in Duke Gerhard I. of Holstein, whose daughter Helvig he married in November, 1276.