Speculative metaphysician al-Kindi used a bit of Aristotle and some clear reasoning to argue that the Universe couldn't be infinite or eternal. Using Aristotle against Aristotle, he reasoned that since a physical thing can't be infinitely large, and since time is an aspect of the physical Universe, the Universe can't be eternal. (Aristotle himself thought that since the motion of the heavens was perfect, the Universe had to be eternal.)
If the Universe were eternal, it would have taken infinity days to get to this one. This means that today couldn't arrive. So the Universe isn't eternal. Now the Big Bang theory is well established, but most post-Newtonian physicists assumed that the Universe had to be eternal. (And post-Spinozan materialists, I might add.)
The trouble is, the infinite-Universe crowd adapted what was basically a neo-Pythagorean piece of mysticism from Augustine and other theologians, who were the first to argue for infinite space.