64 Pa. Stat. § 167
Before any person or persons claiming land north and west of the rivers Ohio, Allegheny and Conewango creek, by virtue of a warrant, shall recover against an actual settler, or his representative, who may have made or commenced an actual settlement on the tract of land claimed by said warrantee, or his representative, the said warrantee or his representative shall prove to the satisfaction of the court and jury, or arbitrators, that the said warrantee, or some person for him, did, within two years from the date of his or their warrant, go on the land so claimed, or attempted to go, and that he or such person was individually prevented by the enemies of the United States from settling said land, and that he or such person did persist, during two years from the date of his or their warrant, to settle and improve the same, or cause the same to be done, and show circumstantially what attempts and what acts of persistence were made, or that he has made or caused to be made such settlement, residence and improvement, as is required by the act of 1792, and within the time therein specified, and that such warrant or warrants were fairly obtained and executed, agreeably to the acts of 1792 and 1785: Provided always, That in all cases where a warrantee, or his legal representative, shall, within two years from and after the first day of April next, tender a conveyance for one hundred and fifty acres, with the usual allowance, including his improvement, clear of all expense, agreeably to the provisions of the act, entitled "an act providing for the settlement of certain disputed titles to land north and west of the rivers Ohio and Allegheny and Conewango creek," passed March 20, 1811, and the said settler shall refuse to accept of the same, in all such cases the actual settler, or those claiming under him, shall receive no benefit from the provisions of this act: And provided also, That nothing contained in this act shall affect any contract or contracts heretofore entered into between any actual settler and warrantee, but the same shall remain as if this act had not been passed.
64 P.S. § 167