Aaron Beck, developer of cognitive therapy, has died.

TRUE: credible obituaries or official announcements (for example from the Beck Institute, the University of Pennsylvania or major newspapers) report that Aaron T. Beck died on or before 1 November 2021, and he is widely credited as the developer or founder of cognitive therapy. MOSTLY TRUE: he had died, but the description 'developer of cognitive therapy' is notably disputed (it is not a minor variant such as 'father of'). FALSE: Beck was alive as of 1 November 2021.

Set before the research began.

1. E1 Dr Aaron Beck: Cognitive behavioural therapy pioneer dies aged 100 BBC · 1 November 2021

   “Dr Beck died peacefully at home on Monday morning, according to a statement from the Beck Institute for Cognitive Behavior Therapy that he and his daughter co-founded.”

2. E2 Dr Aaron Beck: Cognitive behavioural therapy pioneer dies aged 100 BBC · 1 November 2021

   “Dr Aaron Beck, an American psychiatrist considered the father of cognitive behavioural therapy, has died aged 100.”

3. E3 DR. AARON T. BECK, CO-FOUNDER OF BECK INSTITUTE FOR COGNITIVE BEHAVIOR THERAPY, PASSES AWAY AT THE AGE OF 100 Beck Institute for Cognitive Behavior Therapy · 2 November 2021 Own record

   “passed away peacefully in his home in Philadelphia, Pennsylvania, early in the morning on November 1st, 2021, at the age of 100.”

The BBC, in a report dated 1 November 2021, says Dr Aaron Beck died aged 100 and that he died "on Monday morning", citing a Beck Institute statement (E1, E2). The Beck Institute's announcement gives the date of death as the morning of 1 November 2021 (E3), which is on the judging date. The BBC calls him "the father of cognitive behavioural therapy" (E2). That is a minor variant of "developer of cognitive therapy", not a dispute over the description.