The Agile Manifesto and the Twelve Principles of Agile Software sought to change things, speed up development time, and a produce a quality.
The Agile Manifesto is at the core of the Agile Movement.
The Agile Movement was formalized in 2001 with the publication of the Manifesto for Agile Software Development.
The Manifesto reads:
We are uncovering better ways of developing software by doing it and helping others do it. Through this work we have come to value:
Individuals and interactions over processes and tools
Working software over comprehensive documentation
Customer collaboration over contract negotiation
Responding to change over following a plan
That is, while there is value in the items on the right, we value the items on the left more.