The legend of the foundation of Rome by Romulus in 753BC accords very well with the earliest defensive walls on the Palatine Hill, made of clay and timber and showing evidence of animal sacrifices. To trace the continual efforts to fortify Rome is to trace the rise and fall of the Roman Empire - through the taking of the city by the Gauls in 390/387, the wars with the Italian states, the threat of Hannibal, the establishment of the Republic, attacks by the northern tribes and eventual division and collapse. By the 6th century AD, General Belisarius was desperately shoring up the walls with marble slabs from altars and gravestones.
Before the final dissolution, Emperor Aurelius had reunited the Eastern and Western Empires and earned the title of 'Restitutor orbis', restorer of the world. While doing so he initiated the building of the Aurelian Wall, much of which stands today. Its millions of bricks were placed by thousands of workers and 30 years after it was built it would withstand sieges by two Roman armies under Severus II and Galerius. During the civil wars a rampart walk was added over the interior galleries, fronted by a parapet with merlons, so in effect Rome was converted into an extremely large castle. Patton said that 'fixed fortifications are a monument to man's stupidity.' Perhaps the walls of Rome are the greatest example.