From 1652 to 1658, Nikon was not so much the minister as the colleague of the tsar. Both in public documents and in private letters he was permitted to use the sovereign title. This was especially the case during the wars with the Polish–Lithuanian Commonwealth in 1654–1667, when the tsar was away from Moscow with his armies. In 1654, while starting on his great military campaign, the tsar left Nikon at home as the chief ruler. Needless to say, this created some considerable resentment among the high level boyars.