Ernest Doudart de Lagrée was a man who lived a long time ago and did some very important things. He was a French explorer who traveled to faraway places in the world that people didn't know much about. He was very brave and curious, and he wanted to learn more about these places and the people who lived there.
One of the places he went to was a country called Cambodia, which is in Asia. This was a very long time ago, over 150 years ago, when it was very hard to travel to faraway places like that. When he got there, he discovered some amazing things that no one had ever seen before. He saw big temples and buildings that were very old and very beautiful. He also met lots of new people who spoke a different language and had different customs and traditions.
Ernest Doudart de Lagrée didn't just explore Cambodia, he also explored other countries in Asia, like Laos and China. He traveled on boats and on foot, and he even had to fight off some dangerous animals that wanted to hurt him. But he was very smart and knew how to keep himself safe.
Even though he did all these great things, Ernest Doudart de Lagrée didn't get to live a very long life. He got sick when he was only 44 years old and passed away. But even though he's no longer with us, we still remember him today as an important explorer who discovered new places and helped us learn more about the world.