12 events

1969 internet ARPANET

Jul 18, 1969

https://en.wikipedia.org/wiki/History_of_the_Internet
DARPA created the first internet source.

1972 DARPA internet source

Dec 24, 1972

http://www.internetsociety.org/internet/what-internet/history-internet/brief-history-internet#Origins created the secant internet link

1973 TCP/IP enternet

Feb 23, 1973

http://www.tcpipguide.com/free/t_TCPIPOverviewandHistory.htm
the secant internet source.