So, you know how sometimes when you play with your toys, you have to give some toys to your friends to play with too? Well, that's kind of like what happened after World War I.
There were some countries that used to belong to a bigger country called the Ottoman Empire, but they got split up after the war. Some other countries, called the Allied countries, wanted to make sure that these countries would be taken care of and helped to become their own independent nations.
So they decided to create something called the League of Nations Mandate. A mandate is like a job or responsibility.
The job of the League of Nations Mandate was to help countries like Iraq, Palestine, and Syria get back on their feet after the war. The Allied countries didn't want to take over these places and be in charge for a long time, so they gave the job of looking after these countries to other countries.
These other countries were called the mandate powers. The mandate powers were supposed to help the countries they were in charge of. They were supposed to make sure that everyone was safe and that there was a government to run things.
The mandate powers were also supposed to help the people in these countries become more educated and healthy so that they could take care of themselves.
In the end, it didn't work out perfectly because there were a lot of problems and conflicts, but the League of Nations Mandate was an attempt to help countries that needed it after a really bad war.