Baltimore Ravens quarterback Lamar Jackson wears the No. 8. Hall of Fame quarterback Troy Aikman wore the No. 8 when he played for the Dallas Cowboys. The trademark use of the number is now in the middle of a dispute between Jackson and Aikman.

Jackson has filed a challenge against Aikman’s attempt to trademark the use of the No. 8 with the U.S. Patent and Trademark Office, according to a report from ESPN. Jackson has filed two appeals against a company by the name of FL101, which lists Aikman as a director.

Aikman, who is now a color commentator at ABC/ESPN, has attempted to use the No. 8 on bags and other apparel. Jackson, in his complaint, claims that Aikman’s use would be “likely to cause confusion, or cause mistake, or to deceive” the purchasing public as to whether they’re buying products such as a t-shirt or shorts, from Jackson or Aikman’s company.”

Jackson’s filing also said the Ravens quarterback “has expended considerable time, effort, and expense in promoting, advertising, and popularizing the number 8 in connection with his personality and fame” and “is well-known by this number due to his notoriety and fame, along with his promotion of this number in his trademarks and in media coverage.”

Jackson has been making apparel under his “Era 8″ brand and reportedly has applied for multiple trademarks using the No. 8. Aikman, through the FL101 arm, has several products that feature the No. 8. UCLA has retired the No. 8 in honor of Aikman, and no Dallas player has worn the No. 8 since Aikman retired in 2000.