|A medieval merchant weighs sugar for sale|
But let's skip a bit to the European Middle Ages. According to one scholar, the Muslim conquest of Sicily would have introduced sugar to the West:
"Practically all the distinguishing features of Sicilian husbandry were introduced by the Arabs: citrus, cotton, carob, mulberry, both the celso, or black and the white morrella-sugar cane, hemp, date palm, the list is almost endless." — The Barrier and the Bridge-Historic Sicily, Alfonso Lowe (1972)When William II of Sicily (1155-1189) built the Benedictine Abbey of Monreale and made it the largest landowner in Sicily after the Crown, it became one of the largest manufacturers of processed sugar in Europe.
Sugar was wonderful, like honey before it. It could be used to sweeten food, make medicine more palatable, and produce new kinds of drinks. It also could add a decorative touch to food: either by adding sparkle to fruit dusted in sugar crystals, or by caramelizing to a lovely brown on cooked foods.
Still, sugar was not as common as everyone would have liked. In 1226, Henry III (1207-1272) had difficulty finding 3 whole pounds needed for a banquet. Before long, however, production and trade must have increased, because only a generation later, in 1259, Henry could have bought that pound of sugar for only 12 shillings (ginger was 18 shillings, and a pound of cumin was only 2).
To see a collection of recipes from the Middle Ages for sweets, many of which used sugar, see here.