The measure of a master is his success in bringing all men around to his opinion twenty years later.

Summary

This quote suggests that a true master or leader is someone whose ideas and opinions stand the test of time. Their success lies in their ability to influence others and have those individuals eventually adopt and embrace their perspective years later. It implies that a master's effectiveness is not based on instant agreement, but rather on their ability to shape and guide the thinking of others over a longer period, indicating the enduring impact of their ideas and the power of their persuasion.