Assyria in earliest historical times referred to a region on the Upper Tigris river, named for its original capital, the ancient city of Assur. Later, as a nation and Empire, it also came to include roughly the northern half of Mesopotamia.

The Assyrian kings controlled a large kingdom at three different times in history. These are called the Old, Middle, and Neo-Assyrian kingdoms, or periods. The most powerful and best-known nation of these periods is the Neo-Assyrian kingdom, 911-612 BC.