There are about 200 countries in the world today but this number has changed over the centuries. Throughout history, borders have rarely remained static, with new countries forming and others ceasing to exist.

Many nations were created organically as a group of people had a common culture and language. Other countries were formed simply because of geography. Some were created following mass migrations, and some were established after the breakup of bigger empires or countries into smaller states, and others were established following wars and treaties. These are the longest wars in history.

To account for the changes in our world over time, 24/7 Tempo has compiled a list of countries that no longer exist.

Depending on how you count, there are between 195 to 207 countries. There are 193 UN members and two non-member observer states — the Holy See, which governs Vatican City, and the State of Palestine. In addition, there are six states with partial recognition such as Taiwan and Kosovo, and several more self-declared countries.

The world’s newest country is South Sudan, which declared its independence from Sudan in 2011 following a bloody civil war. The smallest country on Earth is the Holy See, which has a landmass of 0.2 square miles within Rome, Italy. Here are the 25 smallest countries and territories in the world.

The oldest country is the Republic of San Marino, which was founded in 301 B.C., but not recognized as an independent country until 1631. San Marino is also surrounded by Italy. Those tiny countries have managed to survive nearly 2,000 years of political upheaval in Europe, a remarkable achievement as political ambitions and nationalist aspirations are forever redrawing the world’s map.

Click here to see the 23 countries that no longer exist and the history behind them

24/7 Tempo used reference materials like Britannica.com, state and country websites, and various biographical websites as information sources to create its list of countries that no longer exist. We considered a variety of reasons for why nations disappeared — losing a war, economic collapse, absorption by a larger, neighboring country. Most of the nations that vanished had been created after the Renaissance, when the notion of a nation-state — countries that have homogeneous features such as language or common descent — first came into being. We included empires such as the Holy Roman Empire, which provided a political, economic, and social framework for the nations that emerged from it.