Complex sentence: The former, fearing their opponents would dominate the new organ, seceded and lobbied the government to allow the formation of an independent Orthodox supracommunal organization, espousing a policy of strict separation from the Neologs.
Split into simpler sentences: The former, fearing their opponents would dominate the new organ, seceded. They eventually convinced the government to allow them to create an independent Orthodox supracommunal organization, espousing a policy of strict separation from the Neologs.