Wikipedia
Anhalt-Köthen
Anhalt-Köthen has existed on two separate occasions. The first state was created in 1396 when the Anhalt-Zerbst was partitioned between Anhalt-Dessau and Anhalt-Köthen. The first creation lasted until 1552 when it was inherited by Anhalt-Dessau.
It was created for a second time in 1603 with the partition of Anhalt-Zerbst. With the death of Prince Augustus Louis in 1774 the principality was split, with the new state of Anhalt-Pless being created.
In 1806 Anhalt-Köthen was raised to a Duchy. With the death of Duke Henry on 23 November 1847 the Anhalt-Köthen line became extinct and its territories were united to Anhalt-Dessau by patent of 22 May 1853.