A distinctive phenomenon of the early years of the Middle Byzantine period, the founding of castles, is linked with the unpropitious historical circumstances of the age. Numerous castles have been located in strategic positions in Macedonia.
The best known is that of Rentina where, in the 10th century, the existing walled settlement was expanded, reinvigorated and chosen as the see of the newly-instituted bishopric of Lete and Rentina.
In the regions of Pydna and the Strymon River, inns of the 11th to the 12th century have been located or excavated. At Peristera, near Thessalonike, a metal-working installation of the 10th century has been investigated.