Cinnamon flavors the holiday season from decorative sweets to soul-warming mulled wine. [Photo provided to China Daily]

You can't make gingerbread without it. Or pumpkin pie. Or mulled wine. Or those glazed sweet potatoes that find their way to holiday tables at the end of December.

"It", of course, is cinnamon, a bestseller on grocery shelves. Second globally only to black pepper among the spices, according to US food giant McCormick, cinnamon was once rare indeed, a flavoring so prized that medieval traders literally died to collect the tree bark that produces it.

Foodies know that there are several "kinds" of cinnamon. Cinnamomum verum, the "true cinnamon" from Sri Lanka that is harvested from only the inner bark, made the island once known as Ceylon a hot spot for traders along the early Silk Road. More common varieties with a stronger flavor come from related species, also coveted by traders for centuries, that are often collectively referred to as "cassia" to avoid confusion with the more potent (and expensive) Sri Lankan species.

As early as the 5th century BCE, Herodotus wrote in his Histories that the "Arabians" obtained cassia by traveling to a great lake and gathering branches and bark on the shores. However, those shores were patrolled by huge batlike, winged creatures which screeched horribly and attacked the spice gatherers. In other accounts, giant snakes guarded the treasure groves of these fragrant shrubs. Considerable heroics thus were required of the harvesters, who－as the stories go－left a portion of what they collected as an offering to the sun god who presumably protected them from these predatory guardians. These tales were not merely the embellished accounts of intrepid travelers: They were crafted by traders to help keep the price of the spice high, and to keep away rival seafarers.

More credible lore about cinnamon is strictly culinary.