Following eight failed attempts on the Matterhorn starting from 1861, Whymper was recalled to London in the summer of 1864 and offered the services of Croz to his friend Adams-Reilly, advising him to make an attempt on the mountain (all three had been in a party that had made the first ascent of Mont Dolent that year). This never came to anything, and the next year Croz was again employed by Whymper. Together with Christian Almer and Franz Biner they made the first ascent of the Grand Cornier, and the first ascent of Pointe Whymper on the Grandes Jorasses.