Logically and theologically, the Assumption is a deduction from the Immaculate Conception and, of course, from the Incarnation itself when the Blessed Virgin, according to the will of the First Person of the Trinity, bore in her body the Second Person of the Trinity by the operation of the Third Person of the Trinity.
It was not until Pope Pius XII issued the Bull Munificentissimus Deus on November 1 1950 that the Assumption was declared an infallible dogma of the Catholic Faith. Sceptics asked why it had taken so long for the Church to notice something so incontrovertibly true. Pope Pius's declaration was underscored by the Second Vatican Council: "The Immaculate Virgin, preserved free from all stain of Original Sin, was taken up body and soul into heavenly glory, when her earthly life was over, and exalted by the Lord as Queen over all things." - Dr Peter Mullen, The Catholic Herald (click below for full article)