Three town halls?

Braunschweig has three different town halls.

Altstadtrathaus

This is the oldest of the three, built in 1200.  On the balcony, there are nine interesting figures on pillars created by Hans Hesse in the 15th century. They represent the Ottonian and Guelf emperors, kings and dukes and their wives. Today, this building is used for exhibition purposes.

The Neustadtrathaus (new city town hall) is not the newest of the three, only newer than the medieval town hall.  It was built in the late 1200's and served not only as the meeting place for the council and the citizens of one of Braunschweig's five districts, but also functioned during the Middle Ages as a central town hall for a common body of all of the districts ("Küchennrath") .

This is the newest of the three.  It was built in the late 1800's and serves today as a typical town hall.  Why does one city need three different town halls?  I don't know, but when I was looking up information on these three, I found out that there might be more than that, closer to six different ones.