The Ascanian lands between the Harz and the middle Elbe, partitioned in 1603 into the Anhalt principalities (Dessau, Bernburg, Köthen and Zerbst), raised to duchies in 1806, and reunited as the single Duchy of Anhalt in 1863 — the only non-Wettin small state in this cluster.
Anhalt became a republic with the German revolution of November 1918; the Free State of Anhalt survived until 1945 and its territory now lies in Saxony-Anhalt.
A dated chronology of Anhalt covering the 1603 partition, the 1806 ducal elevations and the 1863 reunion; polity-specific, verified on Open Library (ISBN 3954622297).