Retsina (Greek: Ρετσίνα) is a Greek white resinated wine, which has been made for at least 2,000 years. Its unique flavor is said to have originated from the practice of sealing wine vessels, particularly amphorae, with Aleppo pine resin in ancient times. Before the invention of impermeable glass bottles, oxygen caused many wines to spoil within the year. Pine resin helped keep air out, while infusing the wine with resin aroma. The Romans began to use barrels in the 3rd century AD, removing any oenological necessity for resin, but the flavor itself was so popular that the style is still widespread today.