Complex sentence: The Portuguese historian Teixeira de Aragão suggests that he studied at the inland town of Évora, which is where he may have learned mathematics and navigation and it has even been claimed (although dubiously) that he studied under the astrologer and astronomer, Abraham Zacuto.
Split into simpler sentences: The Portuguese historian Teixeira de Aragão suggests that he studied at the inland town of Évora, which is where he may have learned mathematics and navigation. It has even been claimed (although dubiously) that he studied under the astrologer and astronomer, Abraham Zacuto.