When did Blaise Pascal invent the wrist watch?

Actually, a German fellow named, Peter Heinlein invented the first portable watch (pocket watch). Blaise Pascal just thought it would be more handy to tie a string around it, and tie it to his wrist. i have searched in many sites, and none say about the exact time he wore a wrist watch. i assume it was during a close time to when the pocket watch was created. even though he did not necessarily invented the wrist watch (he just improved an already made invention) he was the first person reported to wear a watch on his wrist.