To some, the philosophical underpinning of cognitive behavioural therapy goes back to the stoic traditions of ancient Greece and Rome, with the beliefs that we could use logic to deal with any destructive beliefs and feelings. That being said, CBT started to really take off as an alternative to the already commonly used psychotherapies in the 1960s when the theoretical conditioning work of John B Watson and Rosalie Rayner, dating back to the 1920s, began to be read more widely. Early pioneers of CBT were Joseph Wolpe, who is considered one of the most influential people in the development of behavioural therapy, Julian Rotter and B. F. Skinner.