Wien Cod. 13647

[eggyk]

Pisces as two fish connected by a line  is how the actual constellation has always been "parsed" and often depicted in illustrations.  (You are not allowed to view links. Register or Login to view. cites some myths that explain why there are two fish, but not where the idea of a cord came from.)

I thought it simply came from how the constellation looks. 

   

At some point, people started depicting the fish in parallel as well, keeping the tether and stars within that new shape. And sometimes it was just the tether. 

I think that bar belongs to the letter on the previous line, just above the "b".

All the best, --stolfi

Yes, you're right! Thankyou.