The treaty of Vienna, concluded on 1 December 1656, was an Austro–Polish alliance during the Second Northern War.

[1] Habsburg emperor Ferdinand III agreed to enter the war on the anti-Swedish side and support the Polish king John II Casimir with 4,000 troops.

[1] The treaty was, however, dissatisfying for John II Casimir, who had hoped for more substantial aid, and further ineffective as Ferdinand III died three days after giving his signature.

[1] A similar, but more effective alliance was concluded by Ferdinand III's successor Leopold I in the Treaty of Vienna (1657).

This article related to a treaty is a stub.