1657 establishments in the Holy Roman Empire

The Duchy of Saxe-Merseburg was a duchy of the Holy Roman Empire, with Merseburg as its capital. It existed from 1656 or 1657 to 1738 and was owned by an Albertine secundogeniture of the Saxon House of Wettin.

The Duchy of Saxe-Zeitz () was a territory of the Holy Roman Empire established in 1657 as a secundogeniture of the Electoral Saxon house of House of Wettin. Its capital was Zeitz. The territory fell back to the Wettin electoral line in 1718.

thumb|262px|Coat of arms of the Counts of Sayn-Wittgenstein-Hohenstein (1657) Sayn-Wittgenstein-Hohenstein was a county and later principality between Hesse-Darmstadt and Westphalia.