Catholic Answers Director of Apologetics Tim Staples explains when the Church began to canonize saints and why. See the tract linked above for more information.
Tim Staples is Director of Apologetics and Evangelization here at Catholic Answers, but he was not always Catholic. Tim was raised a Southern Baptist. Although he fell away from the faith of his childhood, Tim came back to faith in Christ during his late teen years through the witness of...
"Those who belong to God and Jesus Christ ally themselves with the bishop."
~ Ignatius, Saint, Bishop of Antioch, martyr, and disciple of John; writing to the Philadelphians (Philad, iii, 2) circa A.D. 100, insisting on the necessity of unity with the bishop (from the article "Schism").