This one is totally of academic interest but it's got me puzzled...

I've found an ancient, thin cable tacked to the outside wall of my
1913 house. It's three twisted strands of uninsulated copper wire
(total OD about 1-2mm), which emerges from the concrete ground
adjacent to the house wall, then runs up the wall for about 1.2m where
it is stapled to a wooden windowsill, and has been chopped off, and
the whole become buried in layers of paint over the years. My guess
is the cable originally may have gone through a hole in the sill and
into the house?

This all happens close to the front door, near where all the services
(elec/phone)enter the house.

What would the cable have been for? Some form of earth maybe?

Thanks
David