What is the Oldest Military Branch?

Hey, history-buff here trying to sort out some details, can anyone tell me—which is the oldest military branch, globally speaking?

The oldest military branch in the world is often considered to be the British Royal Navy. It was officially established as a permanent institution under the royal crown by King Henry VIII in the 16th century, around 1546. However, its roots go back even further, with historical records indicating that a permanent navy with ships, crews, and administrative infrastructure existed in England as early as the 13th century.

Please note that there is some debate over this topic because it depends on various factors like how one defines a "military branch", or how far back in history we are willing to look. For example, some might argue that the Roman legions or the armies of ancient city-states could technically qualify as the oldest "military branches". However, in terms of a recognizable form similar to modern militaries, many historians typically point to the Royal Navy.