Treaty of Hadiach
In spite of considerable Roman Catholic Clergy opposition, the Treaty of Hadiach was approved by Polish king and parliament (Sejm) on 22 May 1659, but with an amended text. The idea of a Ruthenian Duchy within the Commonwealth was completely abandoned. It was a Commonwealth attempt to regain influence over the Ukrainian territories, lost after the series of Cossack uprisings (like the Khmelnytsky Uprising) and growing influence of Muscovy over the Cossacks (like the 1654 Treaty of Pereyaslav).