A hunt for the destroyers is underway after UNESCO World Heritage Sites are ruined by graffiti.
According to North Yorkshire police, Fountains Abbey near Ripon was targeted between 18:00 GMT on Friday and 09:00 GMT on Sunday.
Oil-based white paint was used to write “Don't steal drugs” on the medieval plasterwork and St. Mary's Church, a Grade I registered building that is likely to cause “severe” damage. Ta.
Sergeant Danny Copperwheat said the force would “work tirelessly” to bring the person in charge to justice.
He added:
“The North Yorkshire Police do not tolerate these types of conduct.”
He encouraged anyone with information about the person in charge to come forward.
Fountains Abbey is one of two UNESCO World Heritage Sites in Yorkshire, the other being Saltier near Bradford.
The monastery's ruins are the largest in the country, dating back to 1132, when 32 monks left St. Mary's monastery in York and established a new community.
The monastery was disbanded by King Henry VIII in 1539, and the crown sold the property to the merchant, Sir Richard Gresham, before the crown was eventually handed over to the state trust.
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