While there were multiple "lightweight" frameworks that came together under the Agile banner, perhaps the two most important were Extreme Programming (XP) and Scrum.
In 1995, six years before the Agile Manifesto, two papers were presented, a month apart - that laid the foundations for these frameworks.
_Episodes: A Pattern Language for Competitive Development_ was presented by Ward Cunningham at the International Conference on Pattern Languages of Programs was instrumental to forming the new XP framework. _SCRUM Development Process_ was presented by Jeff Sutherland and Ken Schwaber at OOPSLA ’95 a month later that laid the foundation for Scum.
There was creative tension between these two models. _Scrum_ provided a development process that was definable and structured while _Episodes_ provided a pattern language that was dynamic and organic.
It could be argued that one without the other would not have worked - it was the tension in this overlapping ecotone they created in the software community that birthed the Agile Movement. To this day, that creative tension is necessary to make Agile vital - or, in Alexander's words, "alive".
_In a sense, Scrum focused on the transformational process while Episodes focused on the transmutational experience. See more at Flow of Episodes._