Oyo Empire gunshots scared the Oyo cavalry horses and prevented their charging. Dahomey's army also built fortifications such as trenches, which forced the Oyo army to fight as infantry. The battle lasted four days, but the Yoruba were eventually victorious after reinforcements arrived. Dahomey was forced to pay tribute to Oyo. The Yoruba invaded Dahomey seven times before finally subjugating the small kingdom in 1748. With its cavalry, Oyo campaigned successfully in conquest and suppression over great distances. The Oyo army was able to attack defensive fortifications, but it was harder to supply an army, and they withdrew when supplies ran out.
Oyo Empire orders from Oyo were strictly followed, and access to local markets was provided to Oyo merchants. The Oyo often demanded tribute in slaves. The tributary sometimes made war on other peoples to capture slaves for this. Oyo punished disobedience by wholesale slaughter of the community, as it accomplished in Allada in 1698. The Oyo Empire developed a highly sophisticated political structure to govern its territorial domains. Scholars have not determined how much of this structure existed prior to the Nupe invasion. Some of Oyo's institutions are clearly derivative of early accomplishments in Ife. After reemerging from exile in the early