We have records, of jelly like concoctions being eaten as far back as Egyptian times. It is mentioned in Anglo-Saxon recipe books and was a great favourite at banquettes of the likes of Henry VIII
But it was the Victorians who really first played with the endless possibilities that gelatin offers. Jellies were considered quite a luxury as gelatin was quite expensive. This was due to the fact that it had to be purified before use, from sheet form which was extremely time consuming.
It was in 1845 that an American industrialist named Peter Cooper, the man who built the first American steam train, applied for and received US Patent 4084 for powdered gelatin, did it become more widely and readily available.
On the other side of the pond in 1862 in York, a man named Henry Isaac Rowntree first founded the Rowntree sweet company (now known as Hartley's) which was to play a major part in Jelly in the UK from then on.