In the 1480s, complaints lodged by Casimir’s envoys accumulated in Moscow: “thieves” from Muscovy were raiding across the border, burning, and pillaging villages, sowing terror. Ivan professed ignorance and claimed innocence, but clearly the raids had his backing. They were part of a systematic strategy for destabilising the border. Towards the end of the decade they escalated outrageously. In 1487, one of Ivan’s brothers occupied a slice of borderland on the Lithuanian side, and Ivan appointed a governor in districts traditionally part of Lithuania. A raid in 1488 carried off seven thousand of Casimir’s subjects.
– Felipe Fernandez Armesto, 1492, p164, 2009. Reminds me of something but I just can’t quite put my finger on it. Anyway, the Casimir mentioned was the head of the Polish-Lithuanian Commonwealth – yes, there was such a thing. The Ivan was not Ivan the Terrible but a predecessor.