What reforms in the field of government were carried out in the first half of the 19th century?

Under Alexander 1, the collegia were replaced by ministries, because there were a lot of colleges, and management with the help of them was not operational. The judicial function was in the hands of the Senate. The State Council began to be considered the supreme governing body of the country. Under Nicholas 1, the Chancellery was created to develop legislation. Special Committees were created that dealt with state issues and were subordinate only to the emperor.