For the first 12 centuries, contemplation was the normal development of a mature sincere life of prayer.
In the 12th Century, there was an urge to bring more order and method in to prayer. The rising advent of schools of theology meant that scripture was removed from vocal prayer. For various historical reasons prayer began to be compartmentalised.
By the 16th century discursive meditation (thinking about the text), affective prayer (talking to God) and contemplation (being caught up in God) were separate units, distinct ways of praying rather than a series of movements led by the Spirit which could occur in a single period of prayer. Contemplation was regarded as an extraordinary grace, reserved for the few and all but forgotten.
In the 20th Century, a revival began largely due to such people like Thomas Merton. Today we have people like Thomas Keating, Cynthia Bourgeault, Richard Rohr and many more continuing to explore the tradition to facilitate the gift of contemplation.