Who was the final authority over all military matters?

The final authority over all military matters typically rests with the head of state or government, such as a president or prime minister, depending on the country. In many nations, this authority is exercised through a defense minister or equivalent, who oversees the military's operations and strategy. Additionally, in some contexts, the highest-ranking military officer, such as a chief of staff or chairman of the joint chiefs, may also play a significant role in advising and executing military policy.