Complex sentence: Specifically, many studies claim to see references to Freemasonry, which is highly unlikely due to the deep religious beliefs of both Gaudí and Count Güell, nor have these references been proven in the historiography of the modern architect.
Split into simpler sentences: Specifically, many studies claim to see references to Freemasonry, despite the deep religious beliefs of both Gaudí and Count Güell. These references have not been proven in the historiography of the modern architect.