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.. How many years passed from the battle against Valdemar Birgersson to the beginning of the 6000-mark war?