Complex sentence: Plas Machynlleth was the Welsh residence of the Marquesses of Londonderry, situated in the market town of Machynlleth in Powys (formerly Montgomeryshire), Wales.
Split into simpler sentences: Plas Machynlleth was the Welsh residence of the Marquesses of Londonderry. It is situated in the market town of Machynlleth in Powys (formerly Montgomeryshire), Wales.