Allison resigned in 1947, a year after professional football resumed, and his position was taken over by Tom Whittaker, the club's first-team trainer. Intent on playing an expansive style of football, he purchased Don Roper and converted Ian McPherson's position from defender to winger. The changes had the desired effect as Arsenal won the 1947–48 First Division championship. Whittaker won the club's third FA Cup in 1950 and repeated early league success in 1952–53. The club's success began to wane after this, which in turn commenced a stressful period for Whittaker. In October 1956 he died of a heart attack, aged 58. Jack Crayston presided over first-team affairs as caretaker, before he was named permanent manager at the end of 1956. His time was brief compared to his predecessors and left the club in May 1958, achieving a twelfth-place finish in the league.