Isabella herself at last began to entertain doubts about Columbus, and the sovereigns decided to send out Don Francisco del Bobadilla to investigate his conduct. This officer appears to have been needy, passionate, and ambitious. He acted as if he had been sent out to degrade the admiral, not to inquire into his conduct. He threw Columbus into irons, and seized his arms, gold, jewels, books, and most secret manuscripts. Columbus conducted himself with characteristic magnanimity, and bore all indignities in silence. Bobadilla collected testimony sufficient, as he thought, to ensure the condemnation of Columbus, and sent him a prisoner to Spain. The arrival of Columbus at Cadiz, in chains, produced almost as great a sensation as his first triumphant return. A general burst of indignation arose. The sovereigns sent orders that he should be instantly set at liberty, and promised that Columbus should be reinstated in all his dignities. But Ferdinand repented having invested such great powers in any subject, and especially in a foreigner. Plausible reasons were given for delaying his reappointment, and meanwhile Don Nicholas de Ovando was sent out to supersede Bobadilla. _The Fourth Voyage_ (May, 1502--November, 1504) Columbus's thoughts were suddenly turned to a new enterprise. Vasco da Gama had recently reached India round the Cape of Good Hope, and immense wealth was poured by this route into Portugal. Columbus was persuaded that the currents of the Caribbean Sea must pass between Cuba and the land which he had discovered to the south, and that this route to India would be more easy and direct than that of Vasco da Gama. His plan was promptly adopted by the sovereigns, and he sailed in May 1502, on his last and most disastrous voyage. He steered to Hispaniola, but was not permitted to land, and then coasted along Honduras and down the Mosquito Coast to Costa Rica. Here he found gold among the natives, and heard rumours of Mexico. He continued beyond Cape Nombre de Dios in search for the imaginary strait, and then gave up all attempt to find it. Possibly he knew that another voyager, coasting from the eastward, had reached this point. He turned westward to search for the gold-mines of Veragua, and attempted unsuccessfully to found a settlement there. As his vessels were no longer capable of standing the sea, he ran them aground on Jamaica, fastened them together, and put the wreck in a state of defence. He dispatched canoes to Hispaniola, asking Ovando to send a ship to relieve him, but many months of suffering and difficulty elapsed before it came.