Nicolaus Copernicus (1473-1543)

Nicolaus Copernicus
A Polish canon or priest, proposed that the SUN and not the Earth is at the centre of the Universe.
This was dangerous teaching at a time when the Bible was believed to prove that the Earth is the central and most important body of all.
Like Aristarchus 1800 years earlier, it made him unpopular.
He published his theory in a book which very few people bought or read, but the fact that it existed was enough to start others discussing the theory.
However,proof did not come until the century after Copernicus died. His theory was not completely accurate.
First, He believed that the planets move in circles instead of ellipses.
Second, he thought that the stars are dim objects not much farther off than the outermost planet then known, Saturn.
In other words he thought that the Sun was really at the centre of the Universe instead of being an average star in a huge Galaxy.

Source : Wiki