The period between Peter I and Catherine II represents gradual yet significant developments in western culture among the nobility. Tsarina Anna gave many privileges to the nobility. In 1730 she repealed the primogeniture law introduced by Peter the Great allowing the sub-division of estates. In 1736 the age at which nobles had to start service was raised from 15 to 20 and length of service was changed to 25 years instead of life and families with more than one son could keep one to manage the family estate. In 1726 Catherine I and in 1743 Empress Elizabeth further regulated noble dress in a Western direction. In 1755 also during Elizabeth's reign, advanced secondary schools and the University of Moscow were founded with curricula that included foreign languages, philosophy, medicine and law; the material was chiefly based on imported texts from the west. Most significantly Peter III freed the nobility from obligatory civil and military service in 1762, allowing them to pursue personal interests. While some used this liberty as an excuse to lead lavish lives of leisure, a select group became increasingly educated in Western ideas through schooling, reading, and travel. As before, these changes applied to few and represented a gradual shift in noble identity rather than a sudden or universal one. Marc Raeff in "Origins of the Russian Intelligentsia" has suggested this was not a noble victory but a sign the state didn't need them as much now that they had plenty of trained officials.