Woman finds ‘freaky’ hidden ‘Doomsday’ message in the wall of her 150-year-old house

When I finally redecorate, I must remember to write alarming messages for future people.
'Don't turn anticlockwise in here.'
'Have you been in the loft yet? Don't.'
'I never left.'
'I seal the Evil behind this blessed paper and pray that it never be unleashed!'
 
Did they even have permanent markers when this was supposedly written?
Here’s what I found for what it’s worth :
1952

The permanent marker was invented in 1952 by Sidney Rosenthal.
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Permanent marker - Wikipedia