Pesto is thought to have two predecessors in ancient times, going back as far as the Roman age. The ancient Romans used to eat a similar paste called moretum, which was made by crushing garlic, salt, cheese, herbs, olive oil, and vinegar (and sometimes pine nuts) together. The use of this paste in the Roman cuisine is mentioned in the "Appendix Vergiliana", an ancient collection of poems in which the author details the preparation of "moretum". During the Middle Ages, a popular sauce in the Genoan cuisine was "agliata", which was basically a mash of garlic and walnuts, as garlic was a staple in the nutrition of Ligurians, especially for the seafarers.