Okla. Stat. tit. 12 § 1481
In all cases any occupying claimant being in quiet possession of any lands or tenements for which such person can show a plain and connected title in law or equity, derived from the records of some public office, or being in quiet possession of and holding the same by deed, devise, descent, contract, bond, or agreement from and under any person claiming title as aforesaid, derived from the records of some public office, or by deed duly authenticated and recorded, or being in quiet possession of, and holding the same under sale on execution or order of sale against any person claiming title as aforesaid, derived from the records of some public office, or by deed, duly authenticated and recorded; or being in possession of and holding any land under any sale for taxes authorized by the laws of this state, or any person who has made a bona fide settlement and improvement which he still occupies upon any of the Indian lands lying in this state, or any lands held in trust for the benefit of any Indian tribe at the date of such settlement, or which may have heretofore been Indian lands, and which were vacant and unoccupied at the date of such settlement, and where the records of the county show no title or claim of any person to said lands at the time of such settlement; or any person in quiet possession of any land claiming title thereto, and holding the same under a sale and conveyance made by executors, administrators or guardians, or by any other person in pursuance of any order of court or decree in chancery where lands are or have been directed to be sold and the purchasers thereof has obtained title to and possession of the same without any fraud or collusion on his part, shall not be evicted or thrown out of possession by any person or persons who shall set up and prove an adverse and better title to said lands until said occupying claimant or his heirs, shall be paid the full value of all lasting and valuable improvements made on such lands by such occupying claimant, or by the person under whom he may hold the same and all taxes paid thereon by such claimant with interest, as provided for the redemption of lands sold for taxes, previous to receiving actual notice by the commencement of suit on such adverse claim by which eviction may be effected.
Okla. Stat. tit. 12, § 1481