The Phoenicians brought olive trees to Spain around 1050 BC, and the Romans helped spread them, making Spain one of the leading exporters of olive oil. Olive oil was so important that Emperor Hadrian featured an olive branch on coins. Modern storage of olive oil involves large stainless steel or fiberglass tanks in temperature-controlled rooms. Several common varieties of olives grown in Spain are mentioned, including Arbequina, Empeltre, Lechin de Sevilla, Manzanilla Cacereña, and Picual. Olive oil production in Andalusia, Spain involves quality control and certification of origin.