As part of the Queen's Jubilee celebrations, London council workers have been dredging the river Thames. They have turned up a remarkable array of artefacts.
"This is a remarkable, layered, history of London," said Dan Cruikshank, BBC Historian. "Some of these items could be offerings to the gods of the river."
Items brought out of the river include coins going back as far as the Romans, brass spear heads, swords and other jewels, all which support Cruikshank's theory. Where Cruikshanks's detractors feel they have a case, is in other items that have been pulled out of the river.
"Although ancient artefacts could be offerings," said Simon Schama, the BBC's other historian, "they could equally well have been dropped in, or thrown in because they weren't wanted."
The later artefacts recovered from the river dredging supports Schama, with a Vauxhall Nova, three hundred shopping trolleys, numerous traffic cones, hundreds of pounds in coins and a bronze medal from the 1956 Olympics from Melbourne.
"We've identified the medal as the one won by Margret Edwards," said Schama. "And returned it to her, as she is still alive. Apparently, she had no idea where it was. This suggests she never threw it into the river as an offering to a god."
Cruikshank stands by his idea that what many would consider littering and carelessness as religious offerings.
"We see it throughout history," said Cruikshank. "Rivers are a source of great religious fervour. Across the world, indigenous peoples throw into rivers as though there is a primaeval urge to do so. In New York, the Hudson has seen so much thrown off one end, that Manhattan is getting longer. Whilst some don't see this as religious, I believe it is."
Quite what a river god would do with a shopping trolley, nobody is quite sure.
"Go shopping, I presume," said Cruikshank.