There are more than 100 coffee species, but the main commercial varieties are Robusta, Arabica, and – to a lesser extent – Liberica. Robusta, Arabica, and Liberica are three common coffee beans used all over the world. Coffee is considered more than a beverage. It has developed from an energising drink into an international phenomenon. When the plant of coffee, and the beans it produced, was first-ever discovered in Ethiopia in the tenth century, its fame quickly spread throughout the Arabian Peninsula and by the fifteenth-century coffee cultivation and trade was soaring, mainly in Yemen.