Ethicon (plaintiff) was the assignee of the ‘773 patent, which claimed a surgical instrument invented by Yoon, and Ethicon sued Surgical (defendant) for infringement. During its investigation leading up to trial, Surgical learned that Yoon was assisted in developing the surgical instrument claimed in the ‘773 patent by Choi. Surgical and Choi entered into a retroactive license to any patent rights held by Choi in the ‘773 patent. License in hand, Surgical moved the district court to correct inventorship and add Choi as an inventor in the ‘773 patent. After the Court granted the motion and added Choi as an inventor, under the license agreement it had obtained from Choi, which included an assignment of the right to sue for infringement, Surgical moved the Court to dismiss the infringement case. Ethicon appealed.