The natural leader in the plain of Aliakmonas, at the point where Macedonia meets Thessaly and Southern Greece via the straits of Sarantaporos, the castle of Servia was most probably built at some point between the 6th and 7th century A.D. From the late 10th century onwards, Bulgarians, Franks, Serbs, and Ottomans wanted to exploit its strategic position; a position that ensured protection by dividing the castle-city into three parts: the Lower City, the Upper City, and the Acropolis. The military commander resided in the Acropolis, the middle class lived in the Upper City, and farmers and laborers lived in the Lower City.