There is no one date that marks the invention of the bulletproof vest. This is because the invention developed over time, with minor modifications occurring regularly.
One of the first bulletproof vests was the one developed by Filippo Negroli in 1538. Some other examples were developed during the English Civil War, as well as in medieval Japan. However, the first commercially successful bulletproof vest comes from a tailor in Dublin in the 1840s.