Legacy systems keep key business knowledge from companies over time. This knowledge is hidden in the source code lines and must be recovered through software archeology processes to maintain and help the legacy systems to evolve, so that the ROI and lifespan of those systems can be improved. This paper proposes a set of patterns to obtain, in a deterministic manner, business models from the source code of legacy systems. Thus, the business process models recovered from the legacy systems preserve the business knowledge and can be used to modernize and maintain the legacy systems.