but were ultimately controlled by the Benin Empire. The Oba approved the of Esanland, and Esan kingdoms paid tribute to Benin. Yet, several wars between Esan kingdoms and Benin were recorded. This was due to the Oba, at ascension on the throne, sending white chalk to the Esans as a term of friendship. If the chalk was rejected, then the Oba would try to invade Esanland. The varying political stabilities of Benin and the Esan kingdoms also led to warfare. Such warfare was so common that there is no recorded history of peace between all of the Esan kingdoms and Benin. Esanland was extensively involved in world trade. Benin's sovereignty over Esanland enabled it to send long-distant traders, or Ekhen procured cloth, ivory, peppers, and slaves for European merchants in Yorubaland, Esanland, and Afenmai. . During the 16th century, the Uzea War occurred. This war was between the Uromi Kingdom and the Benin Kingdom. The war lasted from 1502 to 1503, and resulted from a refusal of friendship from Oba Ozolua of Benin by Onojie Agba of Uromi. The war ended at the town of Uzea, when both leaders were killed. However, in peaceful times Esan kingdoms would loan soldiers to the Benin Kingdom, such as during the Idah War of 1515–1516, and the sacking of Akure in 1823. During the nineteenth century, northern Esanland was continually attacked and sacked by the Muslim Nupe people in the hunt for slaves and converts to Islam, having previously taken over the Kukuruku peoples' lands. Many Esan kingdoms from the south helped in the battle to fend off the Nupes. The battles came into the Esans' favor; several Nupe and Etsako warriors were brought into Esan cities where their posterity reside today. The nineteenth century brought increasing influence of Europe on Esanland, as the English demanded palm-products. Esan warfare and colonization In 1897, the British launched the Benin Expedition of 1897, which left the Esan independent from the Kingdom of Benin. In 1899, the British led an invasion into the Esan kingdoms that lasted for seven years. Esanland proved to be harder to conquer than the Benin Kingdom because of its strong autonomy: Kingdoms chose to keep fighting the British even if its neighbors capitulated. Defeated Benin chiefs like Ologbosere and Ebohon were still resistant to British rule inadvertently guarded Esan soil from the west, by establishing military outposts and blocking roads. This