Abstract: Some aspects of this disclosure provide methods for phage-assisted continuous evolution (PACE) of proteases. Some aspects of this invention provide methods for evaluating and selecting protease inhibitors based on the likelihood of the emergence of resistant proteases as determined by the protease PACE methods provided herein. Some aspects of this disclosure provide strategies, methods, and reagents for protease PACE, including fusion proteins for translating a desired protease activity into a selective advantage for phage particles encoding a protease exhibiting such an activity and improved mutagenesis-promoting expression constructs. Evolved proteases that recognize target cleavage sites which differ from their canonical cleavage site are also provided herein.