Gottfried Leibniz completed his habilitation dissertation (as part of his book De Arte Combinatoria) in philosophy somewhere in the mid-1660s. Prior to that, he had acquired his master’s degree; what I would like to know is the following:

Did Leibniz’s work for his habilitation come from ideas in his previous studies, particularly his master’s degree work? Or were they novel attempts in their own right? (Also is there any account of any of his earlier works regarding these?)