After the expedition across the Danube, Darius intended to carry his conquests to the west of Europe, not to the north. The cantons of Hellas were the aim towards the attainment of which Megabyzus and Otanes prepared the way. The co-operation of the marine appeared indispensable for further enterprises in this direction. The events at the bridge over the Danube had shown Darius that it was extremely rash to leave in the hands of the tyrants of the Greeks the command of the fleet formed out of the vessels from their cities. The Phenicians he could certainly trust, if he led them against the Greeks, but the navigation of the Greeks had long ago driven the trade of the Phenicians from the Greek coasts. In any case it was advisable that a number of leading Persians should be acquainted with the Greek waters, that they might be entrusted with the command of squadrons. That Persians were equal to such an office had been shown in Africa. Darius commanded fifteen Persians selected by himself to go on board Phenician ships in order to visit and investigate the coasts of Hellas and Sicily. The expedition embarked on two Sidonian ships of the line, which were accompanied by a transport vessel, and set sail from Sidon. On board was a Greek physician as interpreter and guide--Democedes of Croton, who had previously been physician to Polycrates of Samos. He had accompanied his master on his unfortunate voyage to Magnesia (p. 261). After the execution of Polycrates, Oroetes had released the Samians in his company, and retained the rest as slaves in his house. When Bagaeus had caused Oroetes to be slain he sent his property and slaves to the court of the king, where Democedes was kept in rags and chains along with his companions in misfortune. It happened that Darius, in leaping from his horse when hunting, dislocated his ancle. The Egyptian physicians, who were in the greatest repute in the east, and had already been retained since the time of Cyrus at the Persian court (p. 134), could not cure the mischief. At last some one remembered to have heard of the fame of Democedes among the Greeks. Darius caused him to be summoned, and was healed by him. Soon after Democedes cured Atossa, the daughter of Cyrus, the first wife of Darius, of a dangerous tumour in the breast. In return for his successful treatment Darius presented him with two pairs of golden chains; and when receiving them Democedes, according to the Greeks, inquired: Whether the king desired to double his misery in return for the cure? From that time he was in high favour with the king, and was appointed a companion of his table, one of the greatest and rarest distinctions in Persia; it was said to be his intercession which rescued the Egyptian physicians who were about to be crucified because they were unable to heal Darius. He now accompanied the expedition, as a man acquainted with the localities, to Hellas and Sicily, in the year 512 B.C.