Okay kiddo, so there was a long time ago in Ireland called the Irish Sex Aetates Mundi. Sex Aetates Mundi means "Six Ages of the World" and it's basically a way for people to talk about different time periods.
During the Irish Sex Aetates Mundi, people believed that the world went through six different stages. Each stage was really important and had different things happening.
At the start of the first stage, the world was made and everything was pretty new. People believed in gods and goddesses who controlled everything. They also believed that important things happened during certain times of the year, like celebrations and rituals.
In the second stage, people had started to live in groups and form communities. They started to farm and grow food, which meant they could live in one place for a long time instead of always moving around to find food.
During the third stage, people started trading and learning from each other. They also started making things like metal tools and weapons.
In stage four, Christianity came to Ireland and changed a lot of things for the people living there. They started believing in one god instead of many, and they built big churches and monasteries.
The fifth stage was a time of war and conflict. Ireland was invaded by other countries, and there was a lot of fighting over who should be in charge.
Finally, in the last stage, peace returned to Ireland and people started to rebuild. They built new buildings and started to travel more.
So, the Irish Sex Aetates Mundi is really just a way of talking about different times in history in Ireland. It helps us understand how things have changed over time, and how people used to live a long time ago.