If you look at the history of tablature - the lute use 2 main systems.
The French system had the strings the same way up as we do but used letters to represent the frets.
The Italian system had the strings the other way up but used numbers.
These 2 systems existing side by side for a couple centuries with many books published in both.
Introduction to reading lute tablature</a>
We now arrived at our current system of using numbers with the highest pitched strings at the top - but it's only a convention!
