The nobility made up about 1-2% of the population and they were very wealthy landowners who helped the Tsar run the state.
Nobles collected taxes, raised soldiers for the army and held all the senior positions in the military and the Tsarist bureaucracy as provincial governors, commandants of towns and civil servants.
It was birth, not ability that dictated who got the top jobs.
However, Nicholas I was keen to ensure that the sons of nobles were well educated and university places doubled between 1836 and 1848.
It was the educated son’s of the nobility that favoured moderate reforms.