The stargazer with a flair for explanation. Cleomedes (fl. 1st century CE) wrote On the Circular Motions of the Celestial Bodies, a kind of cosmic explainer mixing Stoic physics, Pythagorean echoes, and a heavy dose of astronomy. He preserved key insights from earlier thinkers like Posidonius, especially on things like Earth’s size and eclipses. Less of a discoverer, more of a curator with style. Thanks to Cleomedes, we get a peek into a classroom where the stars came with footnotes.