There has always been more than one possible origin of modern Freemasonry:

- Most Freemasons believe that the Craft has its origin in the Stonemason Guilds of the Middle Ages. According to this theory, at some point in the Guild History, non-operative, or better, Speculative Masons were accepted as members, and later on became the majority in these organisations that changed their names to Freemasonry.
- However, there has always been some suggestions that there is instead a direct connection between the Knights Templar and the present-day Freemasons.

There is no way to know with certainty which theory is true -or even if any of the two theories is true. In this chapter we will analyse in some details the Knights Templar theory of the origin of Freemasonry.