his bandmates' insistence that the group stop touring towards the end of their August 1966 tour of the United States. Afterwards, Harrison informed manager Brian Epstein that he was leaving the band, but was persuaded to stay on the assurance that there would be no more tours. When the group convened to record Sgt. Pepper's Lonely Hearts Club Band in November 1966, there was still a camaraderie and desire to collaborate as musicians; however, their individual differences were becoming more apparent. To a greater extent than the others, McCartney maintained a deep interest in the pop musical trends and styles emerging both in the United Kingdom and the United States, whereas Harrison developed an interest in Indian music and religion, and John Lennon's compositions became more introspective and experimental. In Beatles historian Mark Lewisohn's opinion, Sgt. Pepper represented the group's last unified effort, displaying a cohesion that deteriorated immediately after the album's completion and entirely disappeared by 1968. Epstein's management style was to let the group pursue their musical notions and projects, while often mediating when there was a conflict. This role began to diminish after the band stopped touring in 1966, although Epstein still exercised a strong influence over the band's interpersonal relations and finances. In mid-1967, Apple Corps was initiated under Epstein's oversight as a tax shelter endeavour. However, on 27 August, he died of a medical drug overdose; the consequences of his absence, combined with the Beatles' inexperience as businessmen, led to an unexpectedly chaotic venture that added stress for the band during the coming months. Epstein's death left the Beatles disoriented and fearful about the future. McCartney sought to initiate projects for the group, although his bandmates grew perturbed by his growing domination in musical as well as other group ventures. Lennon later reflected that McCartney's efforts were important for the survival of the band, but he still believed that McCartney's desire to help came from his own misgivings about pursuing a solo career. McCartney felt that the four members' evolution from musicians to businessmen was central to the band's disintegration. Epstein's role as band manager was never replaced, and ultimately the lack of strong managerial leadership contributed significantly to the break-up. Another factor in the split was Harrison's growth as a composer during the second half of their career. Many of his song ideas were rejected by Lennon and McCartney, especially from 1968 onwards. Although