Most of the modern recipes I'm aware of that call for cinnamon tend to mix it with sugar to make baked goods. However, cinnamon was highly valued as a spice even prior to the introduction of sugar. How was cinnamon used prior to the introduction of sugar to the old world? Was it used to add heat to a dish, like pepper or cumin, or did it serve a different purpose in the seasoning of foods?
Sugar is not a “New World” crop at all. It was cultivated in India centuries BC. Plinius wrote about imported sugar from India in the first century AD (see https://books.google.com/books?id=YXGlAr17oekC).
Cinnamon was around much earlier. In Ancient Rome it was common ingredient to add to wine (Roman wine was much less refined than today’s grapes and needed spices to be tasty - if you want to imagine you may try traditional German Glühwein which usually also features cinnamon and other spices).
Cinnamon was also used as an alternative to myrh and incense, for embalming and of course for spicy dishes. The fixation of always adding sugar is a late development of American and European food industry (mainly from the 19th and 20th Century on).
As u/BenMic81 said, sugar isn't New World, the impact of New World sugar plantations was just in availability, not discovery.
I'll look at how it was used by English-speakers before Colombus. Of course you said 'Old World', which also includes say Indian cuisine where it's used in savoury dishes, but this is just what I know and can easily research. The first surviving English cookbook was the 'Forme of Cury' written by a cook of King Richard II around the end of the 14th century, and cinnamon (called 'canel') is a pretty common ingredient. It's used a number of way, often by itself along with other spices for meat or fish. So for instance the recipe for "Plays [plaice] in Cyee [?]" is
Take Plays and smyte hem to pecys and fry hem in oyle. drawe a lyour [mixture] of brede & gode broth & vyneger. and do þerto powdour gynger. canel. peper and salt and loke þat it be not stondyng.
A big thing in the Forme of Cury (and other medieval recipe books) though are premixed spice blends, particularly 'powdour fort' (strong powder) and 'powdour douce' (sweet powder). Cinnamon could be an ingredient in powdour fort (the recipe for "Roo broth" (roe deer) asks for 'powdour fort of gynger oþer [or] of canell", so there were some powder fort mixes where the primary flavour was cinnamon, though the other spices were likely things you might find odd, such as black pepper). There are a couple of surviving recipes for 'powdour douce' (though not from England) which all involve (among other ingredients) sugar and cinnamon, so the taste would probably be fairly familiar to a modern person, though not necessarily how it was used: mostly as a last minute seasoning before serving up on all kinds of mostly savoury dishes, often meat and fish.
The Forme of Cury a couple of times calls for sugar and powdour douce in the same recipe, so it's possible that their version was slightly different though.
From the beginning of the 15th century is the Liber Cure Cocorum which is a cookery book in verse (not a genre that really took off) from the North of England. It's pretty similar, but it's rhyming, so we'll look at it as well. Again, it's a fairly similar mix of being used as a savoury spice, and in much sweeter recipes (which are a bit easier to identify, as a number of the recipes have quantities). The recipe for boiled pheasants and partridges says
Take good brothe, þerin þou pyt [put?]
þy fesauntes and þy pertryks, þat men may wyt [know].
Do þerto ale, floure, peper fre,
Of hole canel, good quantite;
And let alle sethe [boil] þerwyth fulle wele,
And messe hit forthe, Syr, at þe mele.
Powder dowce þerin þou cast,
When hit [is] servyd on þe last.
Here we see whole cinnamon sticks being asked for specifically, where the Forme of Cury usually asked for flour. I've made curries a bit like this before, savoury, with cinnamon sticks stewed in them. On the other hand there's 'momene' which says to add 'sugur þerto ry3t [right] grete plente' and additionally a quart (well actually a 'qwharte') of honey, so a lot sweeter than most chicken recipes we're used to, along with ginger and 'canel rownde' (so whole sticks again). With the exception of a couple of recipes like that though, sugar tends to be used much more like a spice than we're used to.
Lastly, 'A Proper newe Booke of Cokerye' from the middle of the 16th century (so after the discovery of the Americas, but I would have thought before the real rise of Caribbean sugar), and now it's 'synamon' not 'canell', and it is definitely associated with sugar and ginger. This mix is still mostly being used on a wide variety of meat and seafood dishes though, but there are a few desserts in there as well, for instance Applemoyse.
Take a dosen apples and ether rooste or boyle them and drawe them thorowe a streyner, and the yolkes of three or foure egges withal, and, as ye strayne them, temper them wyth three or foure sponefull of damaske water yf ye wyll, than take and season it wyth suger and halfe a dysche of swete butter, and boyle them upon a chaffyngdysche in a platter, and caste byskettes or synamon and gynger upon them and so serve them forthe.
Here it seems to be interchangeable with biscuits for some reason (maybe it means biscuit crumbs).
So in England cinnamon was used in a wide variety of dishes, powdered or whole, and there was definitely a bit of an association with sugar, even from the earliest cookbooks, but also sugar was used much more like a spice itself, and found in a much wider range of dishes. I'd put the move to a pure sweet spice a bit earlier than the other answer, in the 18th century (just looking at a few more cookbooks) but in any case it was well after the discovery of the Americas.