Possibly antibiotics: https://theconversation.com/medieval-medical-books-could-hold-the-recipe-for-new-antibiotics-74490 https://theconversation.com/medieval-m

Possibly antibiotics: https://theconversation.com/medieval-medical-books-could-hold-the-recipe-for-new-antibiotics-74490 https://theconversation.com/medieval-medical-books-could-hol... Not quite so old, but 19th Century ship's logs to learn about weather and climate: https://www.oldweather.org/ https://www.oldweather.org/ Old supernova observations (okay, maybe not vital scientific information, but): https://en.wikipedia.org/wiki/History_of_supernova_observation https://en.wikipedia.org/wiki/History_of_supernova_observati... Quite old: Edmund Halley used Greek star charts to show that stars move in the sky (relative to Earth). Just very, very slowly. https://en.wikipedia.org/wiki/Proper_motion#History https://en.wikipedia.org/wiki/Proper_motion#History