Oba Fredrick Kumokun Adedeji Haastrup, Ajimoko 1, was the 34th Oba of Ijesha land. He was from the Bilaro royal families of Ilesha.

History has it that he was captured by the Ilorins at the age of 14 c.1820s-30s and was sold into Slavery, He was transferred from one slave market to another, finally reaching the coast where he was put on a slave ship chained to other slaves, fortunately, the ship was intercepted by the British Man O' war marines who diverted the slave ship to Sierra Leone.

In Sierra Leone, the young Kumokun met a CMS missionary by name Niels Christian Haastrup, who took a liking in him, Kumokun became his ward and was later Baptized taking the name Fredrick Haastrup. After nearly three decades, he returned home first, arriving in Lagos and later in Ijeṣaland to re-establish contact with his Ijeṣa royalty. In Lagos, he acquired large tracts of property, which became known as Igbó Obį Haastrup, contracted to the present day Igbobį. At Ibeju Lekki, he cultivated Kola-nuts on a commercial scale. His business interests meant he often took the ship up and down the waterways trading in dry fish and other commodities. On one of these journeys, he was instrumental in steering the vessel to safety. He described himself as steering the ship in the manner of a caucasian: Ajimọkọ bi oyinbo.

He became popular in Ijéṣaland during the Kiriji wars when he was a member of the Ekiti parapo solidarity group in Lagos. The organization supplied arms to Ijeṣa warriors who were at war with Ibadan. He was later pivotal in advising the Owá (King) during peace negotiations with the British and Ibadan that brokered the end of hostilities.

In April 1896, when he was well into his seventies, Frederick Kúmókụn Haastrup became the Owá Obokun of Ijeṣaland and took the title Ajimọkọ I (derived from his nickname: 'Ajimọkọ bi Oyinbo'), though he was the first Christian Ọba of Yoruba land. He died on September 1, 1901.