The principal caciques of the island now formed an alliance and uniting their forces laid siege to Santo Tomas. Only Guacanagari refused to join them and hurried to Isabela to offer his services to the Spaniards. At this juncture, on September 29, 1494, Columbus, sick and weary, returned from his voyage, during which, after other discoveries, he had explored a portion of the south coast of the island. As soon as he had recovered sufficient strength he led an expedition into the interior, relieved Santo Tomas, won numerous victories over the natives and founded another fortress, La Concepcion, in the Vega Real, or Royal Plain. Caonabo, however, assembled a vast number of warriors and forced Columbus to renewed efforts. The Spaniards and Indians met where the ruins of the old city of Concepcion de la Vega now are, and the famous battle of the Royal Plain was fought on March 25, 1495. The natives are alleged by the Spanish historians to have numbered 100,000, while the Spaniards had but 200 men and 20 horses, besides the warriors of Guacanagari. In the battle, a bloody one, the Indians were completely beaten, their discomfiture being due principally to the superior arms of the Europeans and the fear inspired by the horses and by twenty blood-hounds brought into the fight by the Spaniards. On the occasion of this battle the miracle of the Santo Cerro, or Holy Hill, is said to have occurred, when, according to the Spanish chroniclers, the Indians captured an eminence on which the Spaniards had erected a wooden cross, but were unable to destroy the cross with fire or hatchet, and were finally frightened away by the apparition of the Virgin Mary. This one crushing defeat definitely broke the Indians' power, for though there were subsequent outbreaks they were only sporadic and, with one exception, of comparatively little importance. Caonabo still remained at large and the Spaniards secured possession of his person by one of those feats of individual prowess which mark the history of the conquest. The Spaniard Alonso de Ojeda went out in search of the cacique, and having found him with his warriors, suggested that they repair to Isabela together to arrange terms of peace with Columbus. The suggestion being accepted, they set out and on crossing the Yaque river Ojeda pressed the Indian to put on a pair of handcuffs, asserting that these bracelets were a distinction of the king of Castile. Caonabo acceded, whereupon the Spaniard sprang upon his horse and swinging the chief upon the croup, fled from the midst of the astonished warriors and bore him a prisoner to Isabela. Caonabo was later embarked for Spain but died on the voyage.