Answer
The war between the Sasanian Empire and the Byzantine Empire, known as the Lazic War, broke out in 540 when the Sasanian king, Khosrow I, invaded the Byzantine province of Lazica on the Black Sea coast. The conflict, which lasted for more than 20 years, was primarily fought over control of Lazica and the Caucasus region, with both sides seeking to expand their influence and secure their frontiers.