 Sir William Blackstone was in no doubt that "the spirit of liberty is so deeply ingrained in our constitution" that a slave, the moment he lands in England, is free.Other prominent lawyers, such as Lord Hardwicke and Lord Mansfield, felt that it was better to recognise slavery, and to impose regulation on the slave trade rather than to withdraw from it, since less enlightened nations would reap the benefits of abolition and slaves would suffer the consequences.The "infidel" argument for maintaining African slaves as chattels was abandoned in the middle of the 18th century, since by then many slaves had been converted to Christianity without gaining "de facto" freedom; and legal justifications for slave ownership were now sought by analogy with the old law of villeinage.