The same year, Wilberforce moved his family from Clapham to a sizable mansion with a large garden in Kensington Gore, closer to the Houses of Parliament. Never strong, and by 1812 in worsening health, Wilberforce resigned his Yorkshire seat, and became MP for the rotten borough of Bramber in Sussex, a seat with little or no constituency obligations, thus allowing him more time for his family and the causes that interested him. From 1816 Wilberforce introduced a series of bills which would require the compulsory registration of slaves, together with details of their country of origin, permitting the illegal importation of foreign slaves to be detected. Later in the same year he began publicly to denounce slavery itself, though he did not demand immediate emancipation, as "They had always thought the slaves incapable of liberty at present, but hoped that by degrees a change might take place as the natural result of the abolition."