Complex sentence: It is named after Prince Idwal Foel a grandson of Rhodri Mawr, one of the ancient Kings of Wales, legend stating that the unfortunate offspring was murdered by being drowned in the lake.
Split into simpler sentences: It is named after Prince Idwal Foel, a grandson of Rhodri Mawr, one of the ancient Kings of Wales. Legend states that the king's unfortunate offspring was murdered by being drowned in the lake.