The spot William chose for his fort had already been built on almost a thousand years before he was born. London was settled by the ancient Romans around the time that they conquered England, in the year AD 43. It was a good place for a city. It was on flat ground that was easy to defend, and it was right on the river Thames, so it was easy for ships to reach. It soon became the biggest and the richest city in England.
In the second century, the Romans built a great wall around their city to protect it. By the time William the Conqueror arrived, the Romans had left England hundreds of years before. But some of their London wall was still there. When William built his fort in London, he used the Roman wall as part of it. It is still there today. This means that the oldest parts of the Tower of London are almost two thousand years old.
William’s original building was probably what is called a motte and bailey castle. A motte is a hill. If there wasn’t a natural hill where the Normans wanted a castle, they would pile up earth to create one. On the top of the hill, they built a fortress. All around the hill, they dug a deep ditch. The area inside the ditch was called the bailey. Around the whole thing, they built a wooden fence.
The original tower that William built in London was finished in only three days. It was made of wood. Soon William decided that he needed something stronger to impress the people of the city. In place of the wooden tower, he decided to build a great stone tower.
He chose a monk named Gundulf to design it. The tower Gundulf built was called the White Tower. He used pale white stone imported all the way from Normandy. It was the biggest building in all of England that wasn’t a church. It could be seen from miles away. It was ninety feet tall with a smaller tower at each corner. The walls of the building were fifteen feet thick at the bottom.
The most important thing about the Tower was that it was a strong fort. To keep everyone safe, there was only one entrance. This was a wooden staircase leading to the middle floor, where a group of soldiers lived. The staircase could be pulled up if necessary. Then no one could get in. The bottom floor stored arms and armor.
The Tower was also a grand castle where the king and his family could live. The upper floor was made rich and comfortable for them. The whole tower was put in the charge of a man called the Constable of the Tower.
Over the years, many smaller towers and buildings grew up around the first tower. In 1097, King William II added a wall that ran all around the outer edge. In the 1220s and 30s, Henry III added ten new towers and a special ditch called a moat. It was filled with water and surrounded the wall. He also had the White Tower painted with whitewash in 1241, so it was truly gleaming white.
Starting in 1275, Edward I added a second wall closing in a large area around the first wall. This meant the Tower was surrounded by two rings of walls. Attackers would have to break through both of them before they could reach the White Tower.
When these kings were finished, in 1285, the Tower of London looked more or less the way it still does today. Gundulf’s huge White Tower stood in the center. It gave the whole collection of buildings and walls its name: the Tower of London.