Later, in Grenoble, Boileau de Castelnau met the President of the Société des touristes du Dauphiné, and in 1876 met the guide Pierre Gaspard and his son. They formed one of the most brilliant ropes of their era, quickly achieving many first ascents in the 1876 and 1877 seasons. On 4 August 1877, Boileau de Castelnau and Gaspard tried a new ascent of the Meije by the south side, a route attempted the previous year by Henry Duhamel. With difficulty and thanks to Gaspard's audacity, they came to the end of the wall that Duhamel thought impassable, both climbing with bare feet. Forced to abandon it due to lack of time, they left a fixed rope in place. On 16 August, Boileau de Castelnau, Gaspard and his son reached the top, not without difficulty: the Meije was defeated. The descent was even more challenging than the ascent and they were obliged to bivouac, on the night of 16 August, on an uncomfortable ledge but managed to return to La Grave the following day. W. A. B. Coolidge, who had hoped to be the first to climb the Meije, initially refused to believe that the relatively unknown Boileau de Castelnau had climbed it. Coolidge himself climbed the Meije by Boileau de Castelnau's route in July 1878 to confirm his account.