Roman and Medieval cookbooks tend to be quite lax in measurements of their recipes, and generally only providing the methods to make something. Which is a far cry from the exact measurements of today’s cookbooks. What exactly started this propensity to have measurements in recipes?
in the united states, fannie farmer introduced standardized measurements for cook books.
she ran a cooking school in boston and needed more exact measurements for recipes
"Overlooked No More: Fannie Farmer, Modern Cookery's Pioneer - The New York Times". Nytimes.com.