The tower of a medieval castle, adjacent to the castle wall or standing free, was a hollow building, taller than the wall. It could have a variety of shapes (rectangular, circular, polygonal, semi-circular, etc.) and serve different functions (such as defensive, residential or observational purposes).

Watchtowers were constructed in numerous forms all over the world. The main function of this type of tower was to observe the enemy (or prisoners). It was commonly built on the area's highest point to ensure a better view.

Gate towers served to protect the gates of a castle or city. The gates were often integrated into the tower. The guards of the gate were stationed inside the building.

A barbican was a fortification outside the main gates of a castle or city that was used to defend the gates. It usually included small watchtowers and was surrounded by a moat. The besiegers could approach the main entrance only through the barbican, which made it impossible for them to fire cannonballs from the front directly at the gate.

A keep was a tower inside the castle walls. It was shorter than a residential tower and was not permanently inhabited. During sieges, it was used by the defenders as a last resort in case the castle was taken.

A residential tower was a fortified free-standing building with massive, thick (2–5 m) walls. It combined every important function (e.g. residential, defensive, storage) and was often surrounded by defensive walls. Most often, it had a rectangular floor plan, but there were round residential towers as well.

Its entrance was placed several metres above ground level to improve the tower's defensibility. When the tower was under siege, the stairs were removed to make accessing the building more difficult.

The residential tower's ground floor was commonly used as a dungeon, while the first floor was usually occupied by a food storage and an armoury. The next floor housed the rooms of the servants. The rooms of the family owning the castle were found on the topmost floor. On the top of the building was a lookout terrace where the guards were stationed.

中世時代の塔と稜堡の種類

中世時代の塔と稜堡の種類

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