Wreathed in history
Wreaths evolved in parallel around the world: olive wreaths were prizes at the original Olympics; the Romans used laurel wreaths as crowns; the Polish celebrated harvest with wreaths of grain; the English decorated maypoles with wreaths of flowers; Tahitian women wear floral wreaths to their weddings.
Christmas wreaths began as rings of greenery (but now can be circles of plastic) and are typically hung on front doors as a welcoming decoration. (Also see advent wreaths on 9 May.)
So, you can see wreaths as:
- A bit of everything
- So confused that you have to ignore a lot of their history and might as well ignore all of it and hence treat them as non-religious
Choose whichever suits your worldview best.
 But wouldn’t have lasted as long as medals, thus reducing athletes’ opportunities to sell their prizes when down on their luck.
 Thus reducing kings’ opportunities of selling off the crown jewels when the treasury was bare.
 With stalks intact, of course. It would be hard to make a wreath from a handful of rye grains.
 Do they toss them like a bouquet at the end of the wedding? (And do they move like frisbees?)