Tabernarius modi sciens instrumenti, paret aptissimu sumer
so assume it's incomplete or possibly idiomatic. You find it scratched in the wall of some ancient ruin in Turkey, over 2000 years old. So, what does it mean?
P.S. It doesn't look like this, the real thing is two separate phrases, scratched into a wall, the comma is the archeologist's doing. Two phrases, possibly incomplete, because part of the wall looks as if it has been repaired at some time (possibly with Roman cement).