Final answer:
Lumley won the case of Lumley v Gye by demonstrating that Gye deliberately induced a breach of contract, which led to a precedent in tort law for recovery of damages from interference with contractual relations.
Step-by-step explanation:
In the case of Lumley v Gye, Lumley was successful in winning the lawsuit by establishing that Gye intentionally interfered with his contractual relations.
This is an early example of the tort of inducing breach of contract. Lumley, who was the manager of a theater, had a contract with an opera singer, Johanna Wagner, to perform exclusively at his theater.
Gye, the director of a rival theater, knew of this contract and induced Wagner to perform at his theater instead. Lumley sued Gye for damages caused by the interference with his contractual relationship with Wagner.
Lumley's victory was due to his ability to prove that Gye had knowingly and willfully enticed Wagner to breach her contract. The court ruled that causing someone to break a contract to someone's detriment was actionable and Lumley was awarded damages.