He was only a linen-draper’s assistant, afterwards becoming a clerk in the Ordnance Office; but the monotony of his work never allowed monotony or narrowness to enter his life. His heart was responsive to every high claim, and difficulties only meant to him obstacles to be overcome. Courage, energy, and determination were his watchwords. His brother was a doctor in Mincing Lane, who saw poor people free of charge, and among his patients was a negro called Jonathan Strong, who had been brought to London by his master, a lawyer, from Barbadoes, only to be turned out into the streets friendless and homeless when he fell ill. Dr. Sharp treated him so successfully that he became quite well, and Granville Sharp found him a situation with a chemist, which he kept for some years, until one day he was seen and recognised by his old employer, who finding him well and active had him seized, and kept in custody until he could be shipped off to the West Indies. Jonathan, in despair, thought of Granville Sharp, and appealed to him for protection. Sharp at once went to the Lord Mayor, who gave judgment that the man had been wrongfully seized and held without a warrant, and ordered him to be at once set at liberty. But then arose an unlooked-for difficulty. Jonathan’s late master had sold him, and his new owner appeared with the bill of sale, claiming his property and declaring he had been robbed. Then came the question as to whether the traffic in slaves which went on openly, especially in London and Liverpool, was lawful or not. Was a slave free when he reached England, or could he be seized and compelled to go back? The lawyers declared that no English law protected the slave. Granville Sharp refused to believe it. During the next few years he spent every hour of his spare time in studying the law; in wading through masses of dry Acts; in sorting, sifting, verifying, and quoting, though more than one friendly lawyer assured him that all his work was a useless waste of time. But the result of his labours surprised them as much as it cheered the heart of Granville Sharp, for it proved that "there was nothing in any English law or statute which could justify the enslaving of others." He at once published a plain, clear pamphlet which he called "The Injustice of Tolerating Slavery in England;" and further than that, certain in the justice of his cause, he went down, armed with a writ of Habeas Corpus, to Gravesend, where he had been told of a captured negro who was being taken back by force. He found the wretched man chained to the mainmast, but after a fierce struggle he got possession of him and returned with him in triumph to London. He did much the same in the case of another negro called James Somerset, whose owner promptly brought the matter before Lord Chief-Justice Mansfield, who declared the question to be so important and doubtful a one that he must take the opinion of the judges upon it. A very lengthy trial followed.