Aurich developed into the unrivalled centre of East Friesia because of the rapid growth of its cattle and horse market, and its reputation spread as far as the Mediterranean region.
The power struggles between East Friesian chieftains meant things were constantly changing in Aurich: different rulers, construction and destruction of their successive strongholds, castles and fortifications.
Aurich blossomed under the Cirksenas, who were ennobled in 1464.They built a new, imposing moated castle on the site of today`s castle, before Aurich was completely destroyed by fire at the beginning of the 16th century in the Saxonian Feuds (Sächsische Fehde).
Trade and craft industry developed rapidly and the rebuilding in the middle of the 16th century shows clear signs of town planning. The basic shape of the market place and the layout of streets and drainage ditches date from this time. Aurich also became a seat of the aristocracy at this time, laying the foundations for its important function as a centre of administration and political representation until today.