Mogens Lauritssøn, also known as Magnus Lauretii (died 3 October 1542, Antvorskov Monastery, Zealand, Denmark), was the 27th and last Roman Catholic Bishop of Hamar.
Nothing is known about the origins of Mogens Lauritssøn. But he is known to have graduated from the in Germany on 17 April 1494 with a degree of magister, that is, doctor. He later became a canon in Oslo and, by 1497, the archpriest of the Cathedral Chapter of Oslo. On 28 January 1513, he was already mentioned as the Electus so the election of the new Bishop of Hamar must have happened either in late 1512 or early 1513. He was still the Electus on 15 July 1513, when he attended a meeting in Copenhagen, but, 12 days later, on 22 July, he was the Bishop. Apparently his consecration must have been performed in Copenhagen between 15 and 22 July 1513.
Of Mogens Lauritssøn, Anton Christian Bang, the Norwegian historian, gave him only a short paragraph in his 1912 book, Den Norske kirkes historie (The History of the Norwegian Church), and remarked:
"He apparently was not without zeal in his office; at any case, he seemed to have frequently gone out on his visitations in his sprawling diocese. He also seemed to be a good man and an ordinary administrator. But, by nature, he was weak and, concerning his abilities, he had certainly not done in this way anything out of the ordinary." (Han synes ikke at have været uden nidkjærhed i sit embede, ialfald sees han hyppig at have væaret ude paa visiatser i sit vidtstrakte bispedømme. Han synes ogsaa at have været en god mand og almindelig afholdt. Men af karakter var han svag, og havd dygtighed angaar, da hævede han sig i denne henseende vistnok ikke over det almindelige.)
But the Bishop of Hamar did have a part in the history of the centuries-long struggle for Norwegian independence. the Archbishop of Niðaros, Olav Engelbrektsson, the Primate of all Norway, and the Riksråd (National Council of Norway) wanted the new King of Denmark and Norway, Frederick I, to respect the independence of Norway so, if he wished to be elected as the King of Norway, he would have to sign their agreement. But, to draft the agreement themselves, they needed his permission to have their meetings in Norway. So, in 1524, the Archbishop sent Lauritssøn to Copenhagen to negotiate with the King. The Bishop was successful. A few months later, the King read and signed the agreement. He was elected as the King of Norway on 5 August 1524, two days before he was formally crowned as the King of Denmark in Copenhagen.