In the spring of 1664, he was dispatched to see Prince Yakov Cherkassky and take charge of his army's clerical work.
In August, however, Grigory Kotoshikhin defected to the Lithuanians and moved to Silesia.
Kotoshikhin converted from Orthodoxy to Lutheran Protestantism and adopted the name Ivan-Alexander Selitsky.
In the fall of 1667, he was executed at Stockholm for killing, while drunk, the owner of the house where he had been living.
Berednikov (St Petersburg, 1840); a modern diplomatic edition with extensive linguistic commentary was published in 1980 by Anne Pennington.