Complex sentence: The site at Millbank was originally purchased in 1799 from the Marquess of Salisbury for £12,000 by the philosopher Jeremy Bentham, acting on behalf of the Crown, for the erection of his proposed Panopticon prison as Britain's new National Penitentiary.
Split into simpler sentences: The site at Millbank was originally purchased for £12,000 from the Marquess of Salisbury in 1799 on behalf of the Crown. A plan was instigated by philosopher Jeremy Bentham for the erection of his Panopticon prison as Britain's new National Penitentiary.