kingdoms
No one ruled Europe in its entirety. The Roman Empire was the largest country in Europe before the Middle Ages, and it was ruled by its emperors. There is a link below to a list of the Roman Emperors, and those who were emperors before 476 AD were emperors before the Middle Ages began.
Europe became a patchwork of little areas of mini-kingdoms.
The greatest threat to the kingdoms was from defeat in war. Most of the early kingdoms did not survive, as those that did survive destroyed the others.
The treaty that divided Charlemagne's empire was the Treaty of Verdun.
kingdoms
Roman Empire fell, and divided among weak kingdoms.
After the fall of Rome what two things caused Western Europe to divide into multiple kingdoms
Domains are divided into kingdoms.
He divided the land into 39 kingdoms and put men in charge of these kingdoms who were in debt to him. If they did something he didn't like he could remove them. He also moved around to each of the kingdoms to keep his power and remind the men he was in charge.
Europe was divide into countries in a way similar to what it is today in many places, primarily by language and culture. Parts of Europe were divided into many kingdoms, and other parts were not. The reasons behind the way things were varied from place to place. The Byzantine Empire was large through much of the Middle Ages, though it tended to get smaller as time passed. France was not quite as large as it is today. The Holy Roman Empire was a good deal larger than modern Germany. After the middle of the 10th century, England was about the same size as it is. There a number of kingdoms within the Holy Roman Empire, but they were feudal territories inside a monarchy, much like counties or duchies. Spain was divided into small kingdoms, which gradually united. Italy had kingdoms and republics, and was basically a number of city states at some points in history. Norway, Sweden, and Denmark were separate kingdoms, but they were united in the Kalmar Union by Queen Margaret I of Denmark.
Western Europe was split into small kingdoms during the Middle Ages. This was a period of European isolation from the rest of the world directly after the collapse of the Roman Empire. Small tribes established their own kingdoms (or even empires). Kings eventually came into play where they established power over a large area, splitting their area into small slices for nobles to rule over. Knights were then protectors of the land, and ordinary citizens and even slaves/serfs lived on the land as well. A kingdom was basically a small, functioning country.
kingdoms
Eukaryacan be divided into four kingdoms. Eukarya covers all organisms in the Kingdom Animalia, as well as the Kingdoms Plantae, Fungi and Protista.
When the western Roman empire collapsed in 476 AD, the unifying force for most of Europe was gone. Along with the loss of the government, much of the engineering abilities and modern amenities were also lost. The Barbarians of Europe did not, for the most part, have the abilities or knowledge to build roads, aqueducts or the other marvels of the Roman Empire, which is why the period immediately after Rome's collapse is often referred to as the "Dark Ages".
Much of Western Europe, perhaps half, was in the Roman Empire or West Roman Empire. The rest of it was in tribal lands and small kingdoms.
No one ruled Europe in its entirety. The Roman Empire was the largest country in Europe before the Middle Ages, and it was ruled by its emperors. There is a link below to a list of the Roman Emperors, and those who were emperors before 476 AD were emperors before the Middle Ages began.