Okay kiddo, let me tell you about José de San Martín. He was a very important man from Argentina who helped to make his country free from Spain.
José de San Martín was born a long, long time ago in 1778 in Argentina. At that time, Argentina was not an independent country. It was ruled by Spain, which meant that the Spanish king had a lot of power over the people who lived there. But San Martín didn't like that. He wanted his country to be free and independent.
So, when he grew up, San Martín decided to become a soldier. He went to Spain to learn how to be a really good soldier. He learned a lot, and then he went to other places like Chile and Peru to help them become independent from Spain, too. San Martín was really good at leading his army and winning battles.
Finally, San Martín and his army were ready to go back to Argentina and fight for their independence. They fought really hard and won some important battles. The most famous one was at a place called San Lorenzo.
San Martín didn't just fight with his army though. He also worked really hard to try and make sure that when Argentina was free, the people would have a good government and a good country to live in.
Finally, in 1816, Argentina became an independent country! San Martín is now seen as a hero in Argentina because he worked so hard to make his country free.