You're probably better off asking the question in reverse -- who was the first to postulate that the stars were merely very distant suns?<br /><br />I don't know if there really is an answer to that question, because it's been speculated for a very long time -- much longer than it's been possible to tell what the "fixed" stars really are. However, the answer is most likely tied up in the question of the Aristotelian cosmology (which held that the stars were fixed to a perfect sphere that was the edge of the known universe). This model was challenged many times; there were even challenges back in antiquity. (Democritus even suggested that the stars could be suns with planets orbiting them.) But when we think about mainstream science turning against geocentrism, we think largely of the Renaissance.<br /><br />The traditional view was that the Earth was the center of the universe, and everything went around it. Well, more or less. There were some variations in this. But by and large, the stars were held to be fixed -- literally. They were either holes in a vast, spherical firmament which allowed the light of the highest Heaven to pass through, or they were lamps attached to the firmament. Either way, fixed. This explained why, unlike the planets, they didn't move.<br /><br />But just as astronomers began to question whether the planets really orbited the Earth, they began to question whether or not the fixed stars were really fixed. By Galileo's time, it was a serious question, although to many it was still considered an absurd notion. Still, it had been suggested that they could be suns just like our own, only very very distant. Giordano Bruno suggested in 1584 that they were suns, and Galileo set out to prove it. Galileo was an ardent supporter of heliocentrism, and if he could find that the fixed stars had satellites, he's have one hell of an argument in his favor. He spent considerable effort mapping the heavens, looking for stars with satellites. Unfortu <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em> -- The Tenth Doctor, "Blink"</font></p> </div>