In the summer of 1898, J. Norman Collie, Hugh Stutfield and Herman Woolley, had made their way up Woolley Creek and initially had their sights on reaching the top of Mount Woolley by climbing the icefield that separates Mt. Woolley from Diadem Peak. However, after a brief downpour which forced them to seek shelter among some rocks, they had just begun preparing the rope for ascending the icefield when a large collapse of ice from the summit made them switch their objective to Diadem Peak. The party ascended the southeast ridge along loose shale and ice, eventually finding a small rock rib that took them to the summit on August 25. Collie recorded an initial elevation of using a mercurial barometer. With the use of crampons, the difficulties of the southeast ridge route are reduced by following a shallow snow gully up much of the way.