What changes did Princess Olga make to the management of the Old Russian state? What is their significance?

The wife of Igor Olga, killed by the Drevlyans, during her reign, made important adjustments in the management of the Old Russian state. Seeing the power of the people, who disagreed with the tyranny of the princes, she realized that it was impossible to do without reforms. Olga introduced Lessons and Churchyards in Russia. Lessons are a fixed rate of tribute collected by the prince once a year. Pogosts are special places for collecting tribute, a kind of branches of power. After these reforms, the princes did not go and collected tribute from the subject principalities, this was done by local authorities.