In April 1960, A.G. Jones conveyed a term royalty interest in several properties to R.L. Peveto (defendant). The conveyance was for a primary term of 15 years and “as long thereafter as oil, gas or other minerals, or either of them is produced . . . in paying commercial quantities.” In November 1973, Jones conveyed to Ernest Starkey (plaintiff) an identical term royalty interest on the same properties, but the deed stated that the grant would become effective only when the deed expired. Approximately four months before the 1960 Peveto deed was set to expire, Jones and Peveto signed an agreement to extend Peveto’s primary term to 25 years. Starkey brought suit for a declaratory judgment against Peveto, seeking an order that Peveto’s term royalty interest was void and that Starkey’s term royalty interest was valid. The trial court ruled in favor of Starkey. The court of appeals affirmed. Peveto appealed.