Yup. It's a 13th-C (we think - the author isn't known, but the two best guesses are both 13th-C authors) treatise aimed at non-Christians (i.e., Jews and Muslims) attempting to prove in a geometrical fashion the truths of Christianity. The whole idea of providing axioms, definitions, and proofs for these things is fascinating, and right up my alley in terms of connecting logic and theology.