There are 20 monasteries on Mount Athos - for men only
Four Moldovan women accidentally breached a ban dating back to 1045 when they were dropped off on the Greek monastic peninsula of Mount Athos.
They told police they had sailed from Turkey after paying $6,300 to two Ukrainian people smugglers, but were unaware they were breaking Greek law.
Women are banned from Mount Athos, home to 20 monasteries and considered Orthodox Christianity's spiritual home.
Police held the group, and one officer said "they were forgiven" by the monks.
The four women, aged between 27 and 32, and a Moldovan man, aged 41, were discovered by the monks at the weekend.
"They told police and the monks they were sorry but they couldn't have known this was a no-women area," a police officer told Reuters.
"They were forgiven."
Under Greek law, breaching the ban can lead to a jail sentence.
Women - even many female domestic animals - have not been allowed on the mountain since a decree banning women was issued by Byzantine Emperor Constantine Monomachos in 1045.