How the World Developed Passports

Passports as we know them are a relatively recent invention in the grand scheme of things. But travel documents of some sort have been around since ancient times. Whether those documents got you into a different country was often a crapshoot. Like many other systems, the birth point of the passport boils down to how you define one. And how you define borders, visas, and rules of passage. You might have guessed by now that the answer to the how and why of passports is war. The journey to the standardized passport was a long and crooked one, since nations don't like to be told what to do, yet most still want their citizens to have freedom of travel. Even today, passport rules are different depending on who you are and where you are going. Not only that, but the rules can change suddenly. Let's hope you are not sitting in an international airport lounge when that happens.