Parchment, paper and the price of memory

A large parchment book could cost an entire flock: every bifolium is an animal. That brutal arithmetic explains half the history of the medieval book — why pages were scraped and rewritten (the palimpsests), why generous margins were a declaration of wealth, why a codex was bequeathed in a will alongside the house.

Paper changed everything twice: first it made writing cheap, then it made printing possible. But parchment never quite left: documents that had to last — deeds, bulls, charters — kept demanding skin for centuries. Memory that mattered was written on something that had been alive.