In many respects, the event in 1973 signalled the beginning of a new era.

The biggest star in the pool at the Munich 1972 Olympics had been Mark Spitz, the first man to win seven gold medals at a single Games.

Australian schoolgirl Shane Gould, still only 15, also returned home a superstar, with three golds, a silver and a bronze.

For different reasons, both Spitz and Gould decided to call a halt to their international careers, but a new cycle of star performers began to emerge in 1973.

Swimming had been amongst the first sports to establish European Championships in 1926, but it was not until the mid 1960s that the concept of a stand-alone World Championships was seriously mooted.

At the time, the international governing body was known as the Federation Internationale de Natation (FINA).

It was a time when many International Federations (IFs) were at loggerheads with the International Olympic Committee (IOC), or more specifically with its autocratic President Avery Brundage.

There were many who believed that the World Championships might lead to a breakaway from the Olympics.

Swimming officials certainly hoped it would generate increased income for the sport.

In April 1968, President Bill Berge Phillips wrote in the FINA bulletin that the time was right and it was soon reported that the Swiss city of Geneva was willing to host them.

The idea was also discussed in meetings at the Mexico 1968 Olympics.

By December, Italian Swimming Federation President Aldo Parodi had also decided that the city of Florence would table a bid.

It was also said that the Brazilians were keen on hosting.

The plan was to include swimming, diving, water polo and artistic swimming, then known as synchronised swimming.

"We laid down the criteria for host countries the requirement including providing meals accommodation and transport for a maximum of 550 competitors coaches and officials for up to 12 days, but there have been no takers," new FINA President Harold Henning revealed.

"The main stumbling block is money," concluded Pat Besford, a respected swimming journalist who later compiled an authoritative encyclopaedia on the sport.

Plans for a world event in 1971 were therefore shelved, but in November that year, swimming officials met in Singapore where Belgrade and Vancouver both tabled bids to host a World Championships in 1973.

Belgrade was chosen by seven votes to five.

"There will be competitions in four specialities," the organisers' bulletin said.

Organisers said the Tasmadjan Centre would be the main "nerve centre" for the Championships but a pool at Stari Grad was being built for what organisers described even then as "artistic" swimming. 

Two training pools were provided at Zverzdra and Vracar.

Banjica was to be used for water polo and Kosvtniak for diving.

Accommodation was arranged for most of the competitors and officials at the Slavia Hotel or the Sumadija Hotel some five kilometres from the city centre for diving.

Yet, in the days before the competition, there was controversy when the Yugoslav authorities refused to grant visas to competitors and officials from Taiwan.

International Federation officials threatened to pull the plug on the entire event but in the end they contented themselves with a "severe reprimand" to the Yugoslavian federation and competition went ahead.

Gould had retired, sated with the demands of international swimming but one of those she had beaten in Munich proved to be a superstar in Belgrade.

Kornelia Ender of East Germany won gold in the 100 metres butterfly and set a world record 57.54 to win the 100m freestyle ahead of Shirley Babashoff of the United States.

Ender also won two further gold medals in the relay.

Renate Vogel, another silver medallist at the Munich Olympics, completed the breaststroke double.

Ulrike Richter won the 100m backstroke, an event she dominated at world and European level all the way to the Montreal 1976 Olympics.

The performances of the East German women were a foretaste of the almost complete dominance they were to enjoy from the mid 1970s until the fall of the Berlin wall in 1989.

"Our girls have done very well, now it is up to our boys to catch up, that is the next thing we will work on," East German Swimming Federation secretary Gert Barthelmes said.

The only East German man to win gold in Belgrade was Roland Matthes - he completed the 100m and 200m backstroke double just as he had done at both the Mexico 1968 and Munich 1972 Olympics.

"The rise of East Germany is certainly the story of the championships," Australian coach Forbes Carlile said.

"It is sure to be a good thing for swimming, they have made a lot of progress in a very short time, it will encourage a lot of other countries."

It was not an opinion universally shared.

"It is so depressing and demoralising just watching them, there isn’t an answer and maybe it isn’t just training," Canadian Donna Marie Gurr suggested.

It was an opinion echoed by many others in the ensuing years but it was not until the fall of the Berlin wall that the full extent of the East German doping programme was revealed.

American John Hencken won the 100m breast stroke in 1:04:02.

He had broken the world record earlier in the day in the heats.

"I felt good in the morning and thought I’d try for the world record," Hencken said afterwards.

"I also felt good in the evening."

In the men’s 200m breaststroke, David Wilkie of Britain, an Olympic silver medallist behind Hencken in Munich, set a world record 2:19.28 to win the World Championships final.

Rick Demont of the United States set a world record to win the 400m freestyle.

He was the first man to swim under four minutes for the distance and recorded a time of 3:58.18.

Demont, an asthmatic, had been stripped of his Olympic gold medal the previous year after traces of ephedrine were found in his sample.

In the 1500m freestyle, Australians had great hopes of 15-year-old Stephen Holland who had broken the world record.

"His two beat kicking in the water is as close to a fish tail action as you can get in a human," his coach Laurie Lawrence said.

Holland justified the expectations to win gold in a world record 15:31.85 ahead of DeMont and fellow Australian Brad Cooper.

In fact, Holland carried on swimming, unaware that the race was over.

"None of us heard the whistle," Holland explained later.

"It is a wonder no one jumped in to stop us."

Holland went on to win gold at the same distance at the Christchurch 1974 Commonwealth Games, though his career ended after a bronze medal at the Montreal Olympics.

Jim Montgomery of the United States completed the 100m and 200m freestyle double, a feat not emulated until Romanian David Popovici did so last year.

There was no doubting the calibre of the men's diving competition.

Italy’s Klaus Dibiasi, already a double Olympic champion, won the 10 metres platform.

Phil Boggs of the United States beat Dibiasi in springboard and repeated the feat at the 1975 World Championships before claiming Olympic gold in 1976.

Sweden's Ulrike Knape won gold in the women's 10m platform and Christa Köhler of East Germany won the springboard.

Water polo was only for the men in 1973 as  Hungary took gold ahead of the Soviet Union.

Among the interested spectators was Ferenc Puskas, the legendary captain of the Hungarian football team which had won Olympic gold in 1952 and reached the World Cup final two years later.

The Americans enjoyed a clean sweep in synchronised swimming, then limited to female swimmers.

Terry Anderson won gold in the solo competition and added silver with Gail Johnson in the duet.

Both of them also won gold in the team event.

Canada took silver in all three events and bronze went to Japan each time.

Japan won six bronze medals in 1973 but did not win World Championship gold until 2001 when the event was first held in Fukuoka.

Miya Tachibana and Miho Takeda won duet gold in synchronised swimming.

Now, the World Aquatics Championships return to Japanese waters in 2023.

They are scheduled to begin in Fukuoka next Friday.