On the penultimate day of racing at the Palau Sant Jordi in Barcelona, the women outshone the men as Franklin and Ledecky wrote their names in the history books and Lithuanian teenager Ruta Meilutyte claimed her second world best of the week in qualifying for the 50 metres breaststroke.
Chad le Clos of South Africa won gold in the men's 100 butterfly to add to his 200 triumph earlier in the week, Brazil's Cesar Cielo blasted to a third straight 50 freestyle title before breaking down in tears on the podium and Dane Jeanette Ottesen Gray cruised to gold in the 50 butterfly.
But the day belonged to Franklin and Ledecky and their performances in the Catalan capital suggest they have every chance of remaining the dominant pair in women's swimming for many years to come.
Franklin's second world 200 backstroke title in a row was her fifth gold of the week and matched a feat previously achieved only by compatriot Tracy Caulkins in 1978 and Australian Libby Trickett in 2007.
She can claim the record for herself if favourites the United States win Sunday's 4x100 medley relay.
Franklin clocked a championship record time of two minutes 04.76 seconds in the 200 backstroke to add to her golds in the 100 backstroke, 200 freestyle and 4x100 and 4x200 freestyle relays. She came fourth in Friday's 100 freestyle.
"Wow @franklinmissy you never stop amazing me," coach Todd Schmitz said on his Twitter feed. "Five golds and we are not done yet."
Franklin set the world record to win 200 backstroke gold at the Olympics last year, one of four titles in London, and also claimed the world title in Shanghai two years ago.
She already has 10 career world championship medals and with eight golds has joined Natalie Coughlin, who first competed at the 2001 edition in Fukuoka, with the most by an American woman.
"This is awesome, I'm exhausted," she told reporters.
"Tomorrow I have the morning off and get prepared for the relay tomorrow night. It's going to be so much fun."
Ledecky smashed the 1,500 metres world best to win gold on Tuesday and also won Sunday's 400 metres when she became only the second woman after Italian world record holder Federica Pellegrini to break four minutes.
|Katie Ledecky of the U.S. poses with her gold medal after setting a new world record at the women's 800m freestyle victory ceremony during the World Swimming Championships at the Sant Jordi arena in Barcelona August 3, 2013. REUTERS/Gustau Nacarino|
Ledecky left Dane Lotte Friis trailing with about 150 metres to go in the 800 and touched well inside the previous record of 8:14.10 set by Britain's Rebecca Adlington to win gold at the 2008 Beijing Olympics.
It was Ledecky's fourth title of the week - she also swam in the victorious U.S. 4x200 freestyle relay team - and she is only the second woman to win all three distance freestyle titles at a single world championships.
German Hannah Stockbauer won the treble at the 2003 edition, also in Barcelona.
After Meilutyte's mark in the 50 breaststroke in the morning session, Ledecky's effort was the sixth world record of the championships, all set by women.
"Four golds and two world records definitely exceed my expectations," Ledecky said in an interview with Spanish broadcaster TVE.
"I'm just thankful to be here and being part of a great team and I feel extremely blessed right now and really happy," she added.
"I don't know (how far I can get). We're going to see in the next couple of years. I'm just going to get back to work and see what I can do."
The capacity crowd reserved the biggest cheer of the night for Brazilian Cielo, who was in floods of tears on the podium as his national anthem boomed out and his nation's flag was raised.
He is the first man to win the 50 freestyle three times and claimed a second consecutive 50 butterfly title on Monday.
"I'm ecstatic, I feel like I'm dreaming," the 26-year-old told French TV, adding that it was a "first step" on the road to the Olympic Games in his home pool in Rio de Janeiro in 2016.
Meilutyte snatched the 50 breaststroke world record in her semi-final about eight hours after Russia's Yuliya Efimova had set a new best in the morning's heats.
The Lithuanian also swam faster than anyone before her in the semi-finals of the 100 breaststroke on Monday and clocked a time of 29.48 seconds in the 50 to beat Efimova's mark of 29.78.
"Two world records is a dream come true," Meilutyte, who took gold in Tuesday's 100 breaststroke final, told TVE.
"I've been really close to the world record and I really wanted it and I'm really happy," added the 16-year-old, who was born two days after Ledecky in March 1997.
(Additional reporting by Emma Pinedo in Madrid, Gregory Blachier in Paris and Josh Reich in London, editing by Ken Ferris)