The Colts left Baltimore at night on March 29, 1984. Here’s the Baltimore Sun front page from the next day.
Like many others, I wish they had changed the name of the team and the uniforms and left the Colts legacy here. When the Patriots play the Colts, I call it “Cheaters vs. Deserters”.
I recommend ESPN’s 30 for 30 program on the Baltimore Colts marching band which stayed together after the team left town. Here’s the trailer. The Blu-ray also includes Bob Irsay’s outrageous drunken news conference.