Much work on technological change agrees that the combination of new and existing technological capabilities is one of the principal sources of inventive novelty, and that there have been instances in history when new inventions appear with few antecedents. The many discussions across research communities regarding the relative roles of combination and origination as sources of technological novelty have not provided much in the way of formal identification and quantification. By taking advantage of the technology codes used by the U.S. Patent Office to classify patents, we discretize technologies and identify four distinct sources of technological novelty. The resulting technological novelty taxonomy is then used to assess the relative importance of refining existing technologies, combining existing and new technologies, and de novo creation of technological capabilities as sources of new inventions. Our results clearly show that the process of invention has been primarily a combinatorial process accompanied by rare occurrences of technological origination. The importance of reusing existing technological capabilities to generate inventions has been steadily rising and recently overtook recombination as the source of novelty for most new inventions.