Warren court forbade the public schools from holding any kind of religious prayers and readings done for a religious purpose much to the chagrin of the conservative section of the society.
Step-by-step explanation:
The Supreme court under Earl Warren was involved in some deep-seated reforms such as Separation of church and the state, School desegregation and the freedom of thought and expression.
It's most influential of all the decision was in separation of church from the state. In the year 1962, the court forbade public schools from conducting prayers and readings specifically meant for religious purposes. Later the courts formulated an establishment clause to check for the conferment of a legislation to the secular credentials of the nation. However private prayer was allowed. The decision remained hotly debated throughout history.