Complex sentence: The early history of the monastery is obscure as regards both names and dates, on account of its being so often referred to under both these titles: whether Zirc and Boccon were separate abbeys cannot now be definitely determined.
Split into simpler sentences: The early history of the monastery is enveloped in much obscurity, as regards both names and dates, on account of its being so often referred to under both these titles. Whether Zirc and Boccon were separate abbeys cannot now be definitely determined.