Question

When parchment which was extraordinarily costly was replaced by papyrus what does the passage mainly discuss?

Answer 1

It discussed that the parchment, animal skin, from some point in time was used as a material to write on. Though it was costly, parchment was durable and stronger than papyrus (come from a plant). 

Papyrus was more economical to use. People tried to transfer the text to this medium. But change was not instant. But there was a time when the church tried to use papyrus because parchment was costly.