Conversation so far:
what took place in London?
On July 28, 2012, Phelps placed eighth in the morning prelims for the 400-meter individual medley.
what did he place after that?
Phelps, the two-time defending Olympic champion, won his heat in 4 minutes.
was this a record breaking time?
13.33 seconds with a time that was well off his world record of 4:03.84 set four years ago in Beijing, when Phelps won a record eight gold medals.

Question: who were other competitors in this competition?
Self-contained rewrite: Besides Michael Phelps, who were other competitors in the London Olympics?