The first ascent was made in 1881 by the Swiss climbers Alexander Burgener and Benedikt Venetz guiding Albert F. Mummery from England. This team had climbed one of the peaks of the neighboring Aiguille des Grands Charmoz the previous year. Two days after an attempt on the East face was found too challenging, they climbed up the couloir separating the Charmoz and Grepon from the Nantillons site to climb the Grepon over the north ridge. The party took a very difficult narrow chimney from just below the col between the peaks. Though Venetz discovered the route and was the lead climber through it, this vertical crevice became famous as Mummery's crack. The party reached the Northern summit, built a cairn and returned, but Mummery wondered at night if the Southern summit they had seen may have been higher. Thus the party came back over the same route two days later and completed a traverse to the highest crag, which involved some abseiling, a broad road suitable for carriages, bicycles, or other similar conveyances, and more spectacular final lead climbing by Venetz, who hauled Mummery to the top after he slipped halfway. The second ascent leader, François Henri Dunod, partly brought up three ladders as he had heard stories of the difficulty of this last pitch, though it turned out there was an easier crack to the top. More than 20 years later this rock climb was still considered to be one of the most difficult in the Alps.