He discovered that the earth revolves around the sun, and gets sentenced to house arrest for the rest of his life. The idea was so far fetched back then, it brought so much fear into the powers that be at that time. They could not handle this, and so they wanted no more than to suppress the information, and the man that discovered this.
Galileo Galilei arrives in Rome to stand trial for advocating that the Earth revolves around the Sun, a criminal heresy to the Roman Catholic Inquisition. Galileo will be found "vehemently suspect of heresy" and sentenced to indefinite house arrest, where he will remain until his death.