This year Erlang celebrates 20 years as a Free Software programming language!

"""
1998 was an exciting year in which the following events occurred:
• The first demo of GPRS20 developed in Erlang was demon-
strated at the GSM World Congress in February and at CeBIT
in March.
• In February, Erlang was banned inside Ericsson Radio Systems.
• In March, the AXD301 was announced. This was possibly the
largest ever program in a functional language.
• In December, Open Source Erlang was released.
• In December, most of the group that created Erlang resigned
from Ericsson and started a new company called Bluetail AB.
"""

Joe Armstrong refers to this time as "Part IV: 1998 – 2001. Puberty problems — the turbulent years", which makes sense, as the language turned 12 in 1998. :-)

"A History of Erlang" (PDF) http://webcem01.cem.itesm.mx:8005/erlang/cd/downloads/hopl_erlang.pdf