A student of Albert Schweitzer and Martin Werner, he attempted to demonstrate the textual link between pre-Islamic Christianhymnody in the Middle East and the composition of the Qur'an. He theorized that the early believers of what later became Orthodox Islam were one of the last communities sticking to a — what Lüling believed to be the true — non-Trinitarian Christian creed, for whom Jesus and the Holy Spirit were not divine. Their theological positions were adopted by later generations and evolved to become an ethno-centric religion of Arabs — Islam. He also proposed that the Meccan and Central Arabian adversaries of Muhammad, the "mushrikun",, were not polytheist pagans but TrinitarianChristians — the associates being Jesus and the Holy Spirit. In early post-prophetic times mushrikun was reinterpreted from its original meaning to become "idolators" or "pagans". An example of what Lüling believes to be the underlying Christian hymn of the Quran is Quran 96, which Lüling believes was originally addressed to Christians not Muhammad. Although Lüling is rarely quoted, his ideas seem to have gained ground among European scholars. German Islam expert Tilman Nagel acknowledged in a 2008 interview these views as a mainstream theory by observing that " has moved towards the other extreme: since the late 1970s you hear that 'the historic figure Mohammed is a fiction, the Qur'an was written and changed during centuries by anonymous writers'. Some Islam experts even believe that the first Muslim community was a Christian Syriac sect". Nagel then refutes this idea, which he considers erroneous. With his approach of research Lüling was an early representative of the "Saarbrücken School" which is part of the Revisionist School of Islamic Studies.
Dispute
According to Alan Dundes, in 1970 Luling submitted a doctoral dissertation which suggested that the Quran "contained evidence of traces of poetic strophic" texts. Dundes writes that Lüling's view was "not in accord with orthodox Islamic tradition", and by 1972, "he was officially dismissed" from the University of Erlangen, where he had submitted his thesis. A lawsuit filed to overturn the dismissal carried on for six years but "did not succeed in reversing the university's action".
