Conversation so far:
who won the super bowl in the 60s
Professional football in the 1960s generally meant one thing: the Green Bay Packers. They won five NFL championships in the decade, including the first two Super Bowls.
when were the green bay packers founded
The Green Bay Packers were founded on August 11, 1919.

Question: when did the team join the nfl
Self-contained rewrite: when did the green bay packers join the nfl