endangered his holdings. In 1644 together with Hetman Stanisław Koniecpolski he took part in the victorious Battle of Ochmatów, in which they crushed forces of Crimean Tatars led by Toğay bey (Tuhaj Bej). In 1644, after the false news of the death of Adam Kazanowski, Wiśniowiecki took over his disputed estate of Rumno by subterfuge. For this he was at first sentenced to exile, but due to his influence, even the King could not realistically expect to enforce this ruling without a civil war. Eventually after more discussions at local sejmiks and then in the Sejm, he won the case and was granted the right for Rumno. In 1646, after the death of Koniecpolski, he became the voivode of Ruthenia. He invaded and took over the town of Hadiach which was also being claimed by a son of Koniecpolski, Aleksander Koniecpolski, but a year later, in 1647, he lost that case and was forced to return the town. On 4 April 1646 Wiśniowiecki received the office of the voivode of Ruthenia, which granted him a seat in the Senate of Poland. He was the third member of the Wiśniowiecki family to gain that privilege. Soon afterward, however, he refused to support King Władysław's plan for a war against the Ottoman Empire, even though the King offered him the rank of a Field Crown Hetman. Then the autumn of 1646, Wiśniowiecki invaded and took over the starostwo kaniowskie vacated recently by banished Samuel Łaszcz. He did so without any legal justifications, which caused a court ruling against him; a ruling that was however never enforced. Later that year, he raised a large private army of about 25,000 for a purpose unknown, as noted by Widacki, who writes that the army, which Jeremi raised with an immense cost for a short time, did not participate in any engagement, nor did it have any clear purpose. He notes that such an army might have been useful in provoking the Ottomans, but as Jeremi was opposed to the war with them up to the point of refusing the hetman office, his actions are puzzling even for the modern historians. Khmelnytsky uprising Wiśniowiecki fought against the Cossacks again during Khmelnytsky Uprising in 1648–51. He received information about a growing unrest, and began mobilizing his troops, and in early May learned about the Cossack victory at the Battle of Zhovti Vody. Receiving no orders from Hetmans