When Galileo became the first person to turn a telescope to the heavens, our vision of the Universe changed. He discovered new data about the Sun, the Moon and the planets that were totally incompatible with the ancient theory that the sky on Earth was immutable and perfect. On the contrary, they strongly supported the rival and novel heliocentric theory of Copernicus.
The Church took him to trial. The ancient system that Galileo discredited had been adopted almost without thinking by the Church and incorporated into its image of the Universe. It fit very well with the biblical data, so for hundreds of years the vision remained accepted. The scientific evidence of Copernicanism was not obtained until 1838.
At the trial, Galileo was convicted and it was not until the twentieth century that the Vatican finally agreed with him.