In Apicius there are recipes related in Book 1 where Romans would preserve different food items by sealing them in jars with plaster in water that had been boil

In Apicius there are recipes related in Book 1 where Romans would preserve different food items by sealing them in jars with plaster in water that had been boiled down to half its volume. While this isn't exactly the same as modern pressure canning the idea of sealing something in a jar and heating it to preserve the contents is 2000 years old, or older as some experts believe Apicius was written starting with Greeks as far back as perhaps 400BC.