The first kingdom to be attacked by the British was the Kingdom of Ekpon. Ekpon launched a fierce resistance against the British invasion on April 22, which nearly destroyed the kingdom. After the near genocide of Esans at Ekpon, the kingdom of Ekpon led an ambush of the British camp at Okueme, on April 29. This led British forces to retreat, consolidate their power, and kill Ologbosere in May. Subsequent attempts by the British failed as well: conquests into Irrua, for example, led to an adoption of a guerrilla warfare strategy followed by a retreat; this method was so successful that other Esan kingdoms adopted it and the British did not invade Esanland until 1901.