The various tribes of the Philippines were frequently at war with each other, as seems to be the invariable rule where a race is broken up into many separate divisions. The weapons used in former times were the bow and arrow, the lance, long curved knives, and in the southern isles the blow pipe (sarbacan), for propelling poisoned darts. The arrows and lances were pointed with iron and bone, or were simply hardened with fire. Their defensive armour consisted of carved wooden shields (carans), inlaid with tortoise-shell and mother-of-pearl, which covered them from head to foot, and also cuirasses formed of bamboo. It is not clear whether they manufactured artillery, but they certainly used cannon of iron and bronze before the advent of the Spanish, at which time the Mindanao tribes held strongly fortified positions--defended with cannon. These fortifications consisted of earthworks and stockades, sometimes surrounded by morasses. Such were the defences of the town of the Chief Rahamora when Legaspi attacked it. This town consisted of four thousand houses, and, having destroyed it, the victorious Spaniards built on its site, in 1571, the city of Manila. The poison used for the sarbacan darts was either derived from certain trees, or, it is said, from the saliva of a green lizard (chacon). The natives are said by Morga to have used this poison in order to kill the Spanish, for whom they had conceived a most bitter hatred. The Manobos and Zambals were the most savage tribes. The Manobos surprised their enemies while asleep, slaughtered the men, and enslaved the women and children. The priest opened the breast of the first victim with the sacred knife, took out the heart, and ate it. This tribe also sacrificed slaves to the god of war, to whom the color red was sacred. They were also head-hunters, and hung these trophies to the roofs of their houses. The Zambals, a fierce and savage tribe, were also head-hunters, as their name signifies, and were in the habit of extracting and eating the brains of slain enemies. Among the Ifugaos the lasso is said to have been used as a weapon.