The founding document, the Agile Manifesto, marks the end of agile's emergence. Notice the careful working.
> We are uncovering better ways of developing software by doing it and helping others do it. Through this work we have come to value ...
An interview requests asks for the emergence of agile. I say, let’s focus on the period between the Byte Smalltalk issue and the Agile Manifesto.
1980
Byte Magazine devotes an issue to Smalltalk. archive 
1985
Laboratory for Teaching Object-oriented Thinking oopsla
1990
1995
Modeling Under Pressure.
report
2000
Agile author's work rebranded as a Manifesto. archive
.
I am asked to recall this period often. I've produced several summaries of high points along distinct dimensions. We offer links as they are remembered.
Episodes in Context chat with John Bywater.
History Of Extreme Programming recounted in wiki.