When Shane Gould broke the 100m freestyle world record, she held all five freestyle WRs from 100m to 1500m. When did she break the 100m world record, to achieve this unique feat?

Shane Gould broke the 100m freestyle world record at the New South Wales State Championship held on January 8, 1972.


https://sahof.org.au/hall-of-fame-member/shane-gould/

The Australian swimmer Shane Gould did indeed hold all those five world records at the same time. She became joint world record holder for the 100m on 30 April 1971 and improved it herself on 8 January 1972 and finally lost it to Kornelia Ender of East Germany on 13 July 1973.

However, the last record she broke--making her hold all five--was for 1500 meters. She did that on 12 December 1971.

Her own Wikipedia page states that she held all five records from 12 December 1971 (when she got the 1500m record) until 1 September 1972. That's probably a mistake, because when looking at each record, she actually lost the record for the 200 meter on 4 August 1972 to the American Shirely Babashoff. She actually regained it on 1 September 1972, but by that time she had already lost the record for the 800 meter to American Jo Harshbarger on 6 August 1972.

The question as posed implicates the time from which Shane Gould was the sole record holder, and that's from 8 January 1972 when she improved her own (shared) record.

The remarkable thing is that when she first held all world records she was fifteen years and seventeen days. If counting only sole record holder, she was fifteen years and forty-six days.

Some Wiki links:
https://en.wikipedia.org/wiki/Shane_Gould#Swimming_career
https://en.wikipedia.org/wiki/World_record_progression_100_metres_freestyle#Long_course_2
https://en.wikipedia.org/wiki/World_record_progression_200_metres_freestyle#Long_course_2
https://en.wikipedia.org/wiki/World_record_progression_400_metres_freestyle#Long_course_2
https://en.wikipedia.org/wiki/World_record_progression_800_metres_freestyle#Long_course_2
https://en.wikipedia.org/wiki/World_record_progression_1500_metres_freestyle#Long_course_2