Lucretius was a really smart ancient Roman man who wrote a big book called “De Rerum Natura”. He was so smart that he thought about the world and how everything in it was made up of tiny particles that you can’t even see!
He believed that everything, including us, was made up of tiny particles called atoms which only come in different shapes and sizes. That was a very smart idea to have in ancient times because it took a long time for other people to figure this out.
Lucretius believed that the world was not created by a god, but it was formed by chance. He thought all the creatures like birds and animals also formed by chance.
He was really concerned about people not knowing enough about the world and how it works, so he wrote this big book to explain all of it in a way that anyone could understand. It was written in an easy-to-read kind of way so that even a 5 year old could understand!
Even though he’s been dead for a very long time, many people still read Lucretius' book today and feel like they understand the world just a little bit better because of him.