Remains of houses have been found as early as 4000 years before the birth of Christ, but it is probably only approx. 700 years before our era, that people began to fortify the city. That this particular place has been chosen is obvious. It is centrally located in the country and in one of the highest places. The buildings were erected in the Arab period from 870 until the Normans conquered Malta. These built a thick fortress wall around the city and a moat, which made the city almost impregnable.