The Vatican is recasting the most famous victim of its Inquisition as a man of faith, just in time for the 400th anniversary of Galileo's telescope and the U.N.-designated International Year of Astronomy next year.

Pope Benedict XVI paid tribute to the Italian astronomer and physicist Sunday, saying he and other scientists had helped the faithful better understand and "contemplate with gratitude the Lord's works."

In May, several Vatican officials will participate in an international...