By the assassination of the two princes who had submitted to Persia the word for revolt was given, and the more plainly because the Barcæans, according to Herodotus, refused to give up the murderers. The land round Cyrene was extraordinarily fertile, and the district of Barca reached on the west to the great Syrtis. The army which set out to reduce a city, 600 miles distant from Memphis, was led by a Persian, Amasis of the tribe of the Maraphians. (V. 323). This march along the north coast through regions partly desert and partly inhabited by nomads, was to be supported by a fleet formed no doubt of Phenician and Egyptian ships, under the command of Badres of the tribe of the Pasargadae. The Persians reached the extensive and well-watered mountain plain which formed the territory of Barca. The city was invested, but the Barcæans made a vigorous resistance. Furious attacks of the Persians were repulsed, and even their attempt to carry mines under the city miscarried. A smith in Barca, according to Herodotus, discovered the direction of the mines by placing a brazen shield upon the ground, inside the wall, and striking it,--the soil being hollow, wherever the shield resounded. Then the Barcæans dug shafts and killed the workmen of the enemy in their passages. After nine months of fruitless efforts Amasis was convinced that he could not take the place by storm. He offered to abandon the siege if the Barcæans would pay a suitable tribute to the king; so long as they fulfilled this condition the Persians would not take up arms against them. The conditions were sworn to on both sides, as Herodotus tells us, in the form that they "should be kept so long as the earth remained." But on the previous night Amasis had excavated the place on which the oath was sworn, had covered the excavation with wood, and placed earth upon the wood. When the Barcaeans, in reliance on the truce, opened the gates, came out of their city and permitted the Persians to enter it, Amasis caused the earth to fall in by removing the wood-work, in order to make the treaty invalid. Being masters of the city the Persians gave up to Pheretima those who were chiefly implicated in the murder of Archelaus. She caused them to be crucified round the walls of Barca, and at the same time cut off the breasts of their wives and affixed them to the walls. The Persians also carried away a large number of prisoners, in order to weaken the city, and so to retain it in subjection with less effort. Only the Battiadæ and a remnant of the population were left. After thus reducing the city, the Persians marched through the fruitful plain, which stretches to the west of Barca between the table-land and the sea, towards the west. At Euhesperides on the great Syrtis they reached the extreme point in the west of Africa to which the Persians ever penetrated.[296]