Most countries around the world did not have an income tax for people before the WWI. It was introduced as a way to fund the wars (defense, akhem), and as a way to come out of the ruins. It was only meant to be a temporary measure. A century later, we're still paying the income tax, and for some countries that's still funding defense/wars...

https://www.investopedia.com/articles/tax/10/history-taxes.a...