(här'lēən, härlē'–) , manuscript collection of more than 7,000 volumes and more than 14,000 original legal documents, formed by Robert Harley, 1st earl of Oxford, and his son Edward, 2d earl of Oxford. In 1753 it was purchased for £10,000 by the British government and with the collections of Sir Robert Bruce Cotton and Sir Hans Sloane formed the basis of the British Museum library.