There’s a great website out there, and if you don’t already know about it, you should. It’s Ancient History Encyclopedia: https://www.ancient.eu/. It’s a curated resource on history, with short, user-friendly articles on a vast array of topics. And it’s more reliable than most online encyclopedias, since the articles follow academic standards and are reviewed by a dedicated team of editors.
In 2016, AHE won the eu Web award for education. Check this out:
AHE has arguably outgrown its name, since its content has moved out of ancient times into the middle ages (Byzantium, etc.). So the site may have what you need, even if it’s not strictly ancient history.
I’m very proud to serve on Ancient History Encyclopedia’s Board of Advisors.