On September 30, 1977, D conveyed real property to the Fogelmans. The Fogelmans then conveyed the property to P. When D conveyed the land it was subject to an undivided one-half mineral interest owned by Texas Osage Cooperative Realty (TOCR). D owned the other undivided one-half mineral interest. D conveyed its whole interest in the land but reserved a one-fourth royalty interest. The deed stated the conveyance was subject to TOCR’s mineral interest; There is hereby excepted from this conveyance and reserved to Grantor, its successors, and assigns, an undivided 1/4th of the royalty covering all of the oil, gas, and other minerals, including but not limited to uranium, coal, lignite, iron, gold, silver, and all other minerals, whether or not now known to be valuable and whether by drilling, strip mining, or any other method, in, to and under or that may be produced from the lands above described . . . . P sued to determine the interests in the minerals. Did D reserve one-fourth of the royalty from the entire 86.82 and 0.003 acres or one-fourth of the royalty from the undivided one-half mineral interest D owned at the time of the conveyance? D argues that the deed reserves one-fourth of the royalty of the entire mineral estate. P argues that the deed reserves one-fourth of the royalty only from the undivided one-half mineral interest D owned at the time of the conveyance to the Fogelmans. The courts below both ruled for D and P appealed.