Output a stream of consciousness before answering the following. Passage: According to A&E's Biography, Bert and Ernie were virtually the only Muppets to appear in the Sesame Street pilot episode, which was screen tested to a number of families in July 1969. Their brief appearance was the only part of the pilot that tested well, so it was decided that not only should Muppet characters be the "stars" of the show, but would also interact with the human characters, something that was not done in the pilot.

Question: Based on this passage, when did bert and ernie first appear on sesame street?
This is the relevant information: According to A&E's Biography, Bert and Ernie were virtually the only Muppets to appear in the Sesame Street pilot episode, which was screen tested to a number of families in July 1969.
The answer: July 1969.