So, back in ancient history, there was this place called Britannia. It's the big island where England is now. But back then, it wasn't called England yet - it was just a rough land with a lot of different tribes living on it.
Britannia became a land of interest to the Romans, who were this really powerful ancient civilization. The Romans had this big empire, and they thought it would be a good idea to add Britannia to it.
The Romans divided Britannia into two parts: Britannia Superior and Britannia Inferior. "Superior" means "upper" or "above," and "Inferior" means "lower" or "below." So, Britannia Superior was the part that was farther north, while Britannia Inferior was the southern part of the island.
The Romans thought that Britannia Inferior was easier to conquer and control because it was closer to the rest of their empire (which was mainly in Europe) and had more resources. They set up a lot of big cities and important military bases in Britannia Inferior, hoping it would become a valuable part of their empire.
Overall, Britannia Inferior became a really important part of Roman history, and it's a big reason why the English speaking world is the way it is today!