His pastoral and educational work was interrupted by the uprising of 1863–1864 and was made extremely difficult as the Russian government tightened its reins after the collapse of the revolt. Yet these circumstances did not prevent him from following a course which could not but bring him into direct conflict with the authorities. He made every effort to undermine the government’s scheme of Russification. In 1874 Valančius fell ill and died in Kaunas on May 29, 1875. He was interred in the crypt of the Kaunas Cathedral Basilica.