They were taken Tuesday from Strängnäs Cathedral, in the town of the same name near Stockholm.
But they were exhumed later and their crowns were put on display.
Britain's own crown jewels were almost stolen in 1671 by Anglo-Irish Colonel Thomas Blood, who was captured as he fled the Tower of London with St Edward's Crown, the Scepter with the Cross, and the Sovereign's Orb.
Eyewitness Tom Rowsell, who is getting married at the cathedral this weekend, described seeing two people running to a "little white boat with a motor on the back".
The thieves have not yet been captured.
Two men reportedly lifted them from locked glass boxes and made their getaway in a speedboat waiting at a nearby waterway.
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The crowns were originally buried with King Charles IX in 1611, and later his wife Queen Christina, as their burial crowns.
'We have some different information about how exactly the boat looked.
It sparked a police search of the lake involving boats and helicopters, but they were unable to locate the thieves.
The objects were on display, but under lock and key, at the cathedral about 50 miles from Stockholm. He also said, "We contacted the police and they told us they had taken something from the cathedral".
Maria Ellior of the Swedish police's National Operations Department told TT that the items are "impossible to sell".
He said it would be hard for the thieves to sell the very recognisable items on the black market.
"The score is 1-0 for them right now, but we don't know what it will be like tomorrow", Agnevik said.