Complex sentence: The name Cremorne from the peer's seat in County Monaghan, is an Anglicisation of what in modern Gaelic is Crìoch Mhùrna, the Bounds of Mourne, from an ancient clan or sept Mughdorna.
Split into simpler sentences: The name Cremorne is from the peer's seat in County Monaghan, and is an Anglicisation of what in modern Gaelic is Crìoch Mhùrna. This means the Bounds of Mourne, from the territorial domain of an ancient clan or sept Mughdorna.