 Complete the following phrase:  At the start of the Attitude Era, following Shawn Michaels injury and subsequent retirement in 1998, Triple H assumed leadership of D-Generation X. At SummerSlam, Triple H defeated The Rock in a ladder match with the help of fellow team member Chyna to win the Intercontinental Champion. At WrestleMania XV, Triple H lost to Kane after Chyna interfered on his behalf and she was thought to have rejoined D-X. Later on in the night, he betrayed his long-time friend and fellow D-X member X-Pac by helping Shane McMahon retain the European Championship and joined The Corporation, turning heel in the process. In April, he started to move away from his D-X look, taping his fists for matches, sporting new and shorter wrestling trunks and adopting a shorter hairstyle. His gimmick changed as he fought to earn a WWF Championship opportunity. After failed attempts at winning the championship, Triple H and Mankind challenged then WWF Champion Stone Cold Steve Austin to a triple threat match at SummerSlam, which featured Jesse The Body Ventura as the special guest referee. Mankind won the match by pinning Austin. The following night on Raw Is War, Triple H defeated Mankind to win his first WWF Championship. He dropped the WWF Championship to Mr. McMahon on the September 16, 1999 episode of SmackDown! before regaining it at 