Task: Question Generation
Input (English): The 6000-mark war was a war between Denmark and Sweden which took place from 1276 to 1278. It started because of a disagreement over an agreed sum of 6,000 silver marks for Danish assistance to Magnus Birgersson in the battle against Valdemar Birgersson in 1275.
Output (English): What was Magnus Birgersson supposed to have been paid for?