Text: By 1568, when Kyoto was at last seized from the Ashikaga shogunate, three ruthless generals Nobunaga, Hideyoshi, and Tokugawa had banded together to eliminate all remaining opposition.
Entailment: By 1568 when Kyoto was seized by the Ashikaga  shogunate, three generals banded together in order to destroy the opposition that was left over.
Contradiction: Once Kyoto was seized the generals immediately turned on each other and began fighting to become the emperor.