Question for the.... Natural historians

From what I can gather, people have been making jam for centuries as a way of preserving fruit. But sugar has only been cheap and widely available for a relatively short time. Even since it has been, there's been periods in relatively recent history when it was scarce. I remember my dad telling me that his mam (my gran) rushed out and bought loads of sugar when rationing ended.

So I've been googling, how to make jam without sugar. All I can find is recipes from the new age hippie folk mentioning stevia and chia seeds, more ingredients that wouldn't have been widely available in the UK years ago, yet it seems people still managed fine.

Does anyone know how you make jam without added sugar or other more quirky ingredients?

 

They used honey.

 

@Jocko is right, honey was the common sweet preservative. I also remember from school that Romans were very clever in using all sorts of preservatives to prevent microbiological growth, heavy metals and poisonous minerals being popular. I guess it was nicer to die from accumulating lead poisoning than a sudden food poisoning.

Here's an interesting article

National Center for Home Food Preservation | NCHFP Publications

 

History Of Jam, Jelly, & Preserves