Each lord, in his castle, was supreme in authority over the vassals subject to his sway.

Life and death were in his hands.

The fealty he owed his sovereign was paid in a small tribute, and in military service with an appointed number of soldiers whom he led into the field and supported.
Having thus secured safety in the north, Oleg turned his attention to the south.

With a well-disciplined army, he marched down the left bank of the river, sweeping the country for an hundred miles in width, everywhere planting his banners and establishing his simple and effective government of baronial lords.

It was easy to weaken any formidable or suspected tribe, by the slaughter of the warriors.