Although the theory of evolution was first articulated in the 1850's, the Roman Catholic Church didn't address the issue formally until the 1950's.
When the Catholic Church eventually spoke on the issue, specifically Pope Pius XII in 1950, he stated that there was no conflict between evolution and Christian faith.
The official catechisms of the Catholic Church (revised 1997) state:
Faith and science: "... methodical research in all branches of knowledge, provided it is carried out in a truly scientific manner and does not override moral laws, can never conflict with the faith, because the things of the world and the things of faith derive from the same God. The humble and persevering investigator of the secrets of nature is being led, as it were, by the hand of God in spite of himself, for it is God, the conserver of all things, who made them what they are." (Vatican II GS 36:1)
The question about the origins of the world and of man has been the object of many scientific studies which have splendidly enriched our knowledge of the age and dimensions of the cosmos, the development of life-forms and the appearance of man. These discoveries invite us to even greater admiration for the greatness of the Creator, prompting us to give him thanks for all his works and for the understanding and wisdom he gives to scholars and researchers....
- The great interest accorded to these studies is strongly stimulated by a question of another order, which goes beyond the proper domain of the natural sciences. It is not only a question of knowing when and how the universe arose physically, or when man appeared, but rather of discovering the meaning of such an origin....
Pope John Paul II said in a 1996 address:
"In his encyclical Humani Generis (1950), my predecessor Pius XII has already affirmed that there is no conflict between evolution and the doctrine of the faith regarding man and his vocation, provided that we do not lose sight of certain fixed points.... Today, more than a half-century after the appearance of that encyclical, some new findings lead us toward the recognition of evolution as more than a hypothesis. In fact it is remarkable that this theory has had progressively greater influence on the spirit of researchers, following a series of discoveries in different scholarly disciplines. The convergence in the results of these independent studies—which was neither planned nor sought—constitutes in itself a significant argument in favor of the theory."
Pope Benedict XVI (Joseph Ratzinger) said in 2008:
“The theory of evolution does not invalidate the faith, nor does it corroborate it. But it does challenge the faith to understand itself more profoundly and thus to help man to understand himself and to become increasingly what he is: the being who is supposed to say Thou to God in eternity.”
The Catholic Church's position on creation and evolution pleased some and upset others. Some of the devout, who desired that the Church align itself with current scientific consensus, welcomed the position, seeing it as progressive and modern. Other believers expressed disappointment because they thought the Church was falling away from a literal interpretation of the Bible, especially in regards to the book of Genesis.