According to an inscription found next to the eastern town gate of Emona, on the site of the present Trg francoske revolucije square, the Roman town walls were built between 14 and 15 AD. The rectangular-shaped walls surrounding the town centre measured 2.4 metres wide and from 6 to 8 metres high. They included at least 26 towers and four main gates. The towers were erected at equal distances along the length of the walls and next to the town's side gates as extensions of Emona's roads. On all sides except the east, which was naturally protected by a slope descending towards the Ljubljanica river, the town was additionally protected by a double moat.
The wall shell was built from carved stone blocks bound with mortar and filled with a conglomerate of river pebbles, small rocks, sand and lime. The wall structure was so solid and robust that certain parts of the wall survived for as long as 2,000 years. The inner structure of the wall is visible in the Mirje suburb, the location of the part of the walls which stood to the west of the main southern gate of Emona. For security reasons some of the side gates had been walled up already in Roman times to ward off attacks from barbarian tribes. One of the surviving walled-up gates can be seen in the western part of the walls in Mirje.
In the 1930s, the town wall complex in Mirje was restored to a design by the architect Jože Plečnik. His additions to the surviving Roman walls include a stone pyramid, upward extensions of the walls, the gates to the wall complex, an arched vault covered in stone remains from nearby Roman buildings, and a park inside the walls. Also the colonnade next to the main southern gate is of non-Roman origin. The walls were renovated in the 1990s.References:
The moated castle at Beersel is one of the few exceptionally well-preserved examples of medieval fortifications in Belgium. It remains pretty much as it must have appeared in the 15th century. Remarkably, it was never converted into a fortified mansion. A visitor is able to experience at first-hand how it must have felt to live in a heavily fortified castle in the Middle Ages.
The castle was built in around 1420 as a means of defence on the outer reaches of Brussels. The tall, dense walls and towers were intended to hold any besiegers at bay. The moat and the marshy ground along its eastern, southern and western edges made any attack a formidable proposition. For that reason, any attackers would have chosen its weaker northern defences where the castle adjoins higher lying ground. But the castle was only taken and destroyed on one occasion in 1489, by the inhabitants of Brussels who were in rebellion against Maximilian of Austria.
After being stormed and plundered by the rebels it was partially rebuilt. The pointed roofs and stepped gables are features which have survived this period. The reconstruction explains why two periods can be identified in the fabric of the edifice, particularly on the outside.
The red Brabant sandstone surrounds of the embrasures, now more or less all bricked up, are characteristic of the 15th century. The other embrasures, edged with white sandstone, date from the end of the 15th century. They were intended for setting up the artillery fire. The merlons too are in white sandstone. The year 1617 can be clearly seen in the foundation support on the first tower. This refers to restorations carried out at the time by the Arenberg family.
Nowadays, the castle is dominated by three massive towers. The means of defence follow the classic pattern: a wide, deep moat surrounding the castle, a drawbridge, merlons on the towers, embrasures in the walls and in the towers, at more or less regular intervals, and machiolations. Circular, projecting towers ensured that attacks from the side could be thwarted. If the enemy were to penetrate the outer wall, each tower could be defended from embrasures facing onto the inner courtyard.
The second and third towers are flanked by watchtowers from which shots could be fired directly below. Between the second and third tower are two openings in the walkway on the wall. It is not clear what these were used for. Were these holes used for the disposing of rubbish, or escape routes. The windows on the exterior are narrow and low. All light entering comes from the interior. The few larger windows on the exterior date from a later period. It is most probable that the third tower - the highest - was used as a watchtower.