A Brief History of Cosmology People have been putting together cosmological histories for thousands of years. The majority of these, however, involve scenarios such as Earth being formed out of the eyebrow of a frost giant, and are not supported by the most modern data. We will therefore start our story with the flrst attempts at quantitative, predictive models of the universe, which began with the Greeks. The Greeks were superb mathematicians and considered geometry to be the height of math- ematics. They therefore interpreted observations in a way that involved mathematical aesthetics. For example, multiple lines of evidence pointed to a roughly spherical Earth (shadows on the Moon; difierent constellations becoming visible as one went south; apparent sinking of ships as they went towards the horizon in any direction). They generalized this to the idea that everything in the heavens is on spheres as well (at difierent radii). Since the \natural" motion of a sphere is to rotate, it followed that t...