Python, I'd argue, is very much a living language. It was introduced in 1990, so it's 29 years old. Last release was 5 days ago as I write this [1]
Java, is also a living language. It was introduced in 1995, so it's 23 years old. Last release was in September 25 [2]
Cobol was introduced in 1959, so it's 1959. [3] The last table release was 2014 (which is a lot newer than I would have expected). Cobol is a great object lesson, I think, as the parent comment calls out. I don't think many software engineers would consider it a "modern" language, but according to the Wikipedia article, as of 2012, 60% of businesses use Cobol. So it's far from a "dead" language.
Lisp was introduced in 1958... 61 years old. [4]. I don't think many developers would consider Lisp dead, either.
Cobol's longevity seems to be tied to the fact that much of the legacy code encapsulates business logic, as opposed to UX logic (websites, mobile apps, etc.) There's more than a few lessons in there I think...
[1] https://en.wikipedia.org/w/index.php?title=Python_(programmi...
[2] https://en.wikipedia.org/w/index.php?title=Java_(programming...
[3] https://en.wikipedia.org/w/index.php?title=COBOL&oldid=88324...
[4] https://en.wikipedia.org/w/index.php?title=Lisp_(programming...