In 1275  Count Floris V of Holland (province of South Netherlands today), in an attempt to win the support of Amstel-land peasants in his struggle against rival lords and nobles, grants Aemstelledammers exemption from the tolls in his county. It would be the first ever written mention of the settlement with the name of Aemstelredamme in history.

Count Floris V (r. 1256 – 1296) managed to annex the lands of his rival lords on the north and become the safe-keeper of the interests of the Bishop of Utrecht John I until he was assassinated in 1296 a few kilometers away from Amsterdam. After his assassination, the region passed again under the direct control of the Bishopric of Utrecht.,_Count_of_Holland,_Count_of_Holland#/media/File:Vloot_van_Floris_V_van_Holland_(1288),_RP-P-1937-1876.jpg