One of the first men's wrist watches before the Great War was the Cartier "Santos" (a version of which Cartier still produce to this day). The original version was commissioned in 1904 by aviator Alberto Santos-Dumont because he was frustrated with pocket watches while piloting his aircraft. He needed something he could glance at without letting go of the controls.

So he asked friend and jeweller Louis Cartier to design a wrist watch he could wear while flying. Mass production began in 1911, when Cartier saw the potential and began producing the Santos for the public.

That is around the start of men's wrist watches but as I said before they really took off after the Great War. It was trench warfare that really changed things. Much like Santos, soldiers found it cumbersome to take a pocket watch in and out of their pocket frequently, which was needed as military manoeuvres were often precisely timed.

Some of the soldiers repurposed pocket watches by soldering or welding metal lugs onto the case. These lugs allowed them to attach straps and wear the watch directly on their wrist.

After the war this new trend continued with military men (the "manliest of men") continuing to wear wrist watches, making them acceptable for everyone.

To this day a lot of the styles of watch relate to their use in the military as tools. Field watches, pilot's watches. Even some dress watches, besides the Santos already mentioned Louis Cartier also designed the "Tank" in 1917, drawing direct influence from the look of the Renault FT-17 military tank, if viewed from above.

@ruari I always wondered about wrist watches, but the history is a bit modern for me (I lean more into Victorian history). Thank you for this thread.