Asteroid may have caused conversion of Constantine
Claims are being made that an asteroid which exploded like a nuclear bomb may have converted the Roman emperor Constantine to Christianity.
Scientists have discovered an impact crater dating from the fourth of fifth century in the Italian Apennine mountains.
They believe the crater in the Sirente mountains, which is larger than a football field, could explain the legend of Constantine's conversion - who is often credited with creating the first alliance of church and state.
Accounts from the 4th century describe how barbarians stood at the gates of the Roman empire while a Christian movement threatened its stability from within.
It is said the emperor saw an amazing vision in the sky, converted to Christianity on the spot, and led his army to victory under the sign of the cross.
The story is viewed with very mixed feelings, particularly by those from a peace church tradition and who believe in a clear separation of church and state.
Swedish geologist Jens Ormo discovered the crater after spotting a photograph of an unusually round lake in Italy's Sirente-Velino Regional Park.
A visit to the site quickly identified several tell-tale features of an impact crater, New Scientist magazine reported.
The seasonal lake, 140 metres across, had a pronounced raised rim and no inlet or outlet, being filled by rainfall.
Ormo's team believe they were made when an asteroid about 10 metres in diameter shattered during entry into the atmosphere.
New Scientist said: "From the crater size, Ormo estimates that the impact had an explosive force of a kiloton - equivalent to a very small nuclear weapon. Indeed, it would have looked like a nuclear blast, with shock waves, earthquakes and a mushroom cloud."