Long pepper (Piper longum), sometimes called Indian long pepper, is a flowering vine in the family Piperaceae. It is cultivated for its fruit, which is usually dried and used as a spice and seasoning. Long pepper has a similar, but hotter, taste to its close relative Piper nigrum from which black, green and white pepper are obtained; the latter is actually just a ripened form of black pepper. The word 'pepper' itself is derived from the Prakrit word for long pepper, pipali.
The fruit of the pepper consists of many minuscule fruits - each about the size of a poppy seed - embedded in the surface of a flower spike that closely resembles a hazel tree catkin. Like Piper nigrum, the fruits contain the alkaloid piperine, which contributes to their pungency. Another species of long pepper, Piper retrofractum, is native to Java, Indonesia. The fruits of this plant are often confused with chilli peppers, which belong to the genus Capsicum and were originally from the Americas.
The first reference to long pepper is found in the ancient Indian textbooks of Ayurveda where its medicinal and dietary uses are described in detail. It became known in classical Greece around 400 BC where it was mentioned by the playwrights Antiphanes, Eubulus, Alexis and in a Hippocratic text, although Hippocrates discussed it as a medicament rather than a spice. Among the Greeks and Romans, and before the European rediscovery of the Americas, long pepper was an important and well-known spice being imported from north-eastern India. In fact, pepper was the quintessential spice of the Indian Ocean trade whereby large quantities of Roman gold and silver coins made their way into the markets of India. So important was this trade that the Roman treasury stockpiled pepper, especially in the horrea piperatoria ('pepper warehouses') built by Emperor Titus Flavius Caesar Domitianus Augustus (Domitian), as an alternative form of currency. For those who could afford 'exotic' pepper, Apicius mentions it over 400 times.
The ancient history of black pepper is often interlinked with (and confused with) that of long pepper even though Theophrastus distinguished the two in the first work of botany. The Romans clearly knew of both but, confusingly, often referred to either as just piper; Pliny erroneously believed dried black pepper and long pepper came from the same plant. Long pepper (piper longum) is the hotter of the two, however, with Galen comparing its heat to that of ginger. It fetched twice the price of black pepper in Roman times.
Round, or black pepper, began to compete with long pepper in Europe from the 12th-century and had largely displaced it by the fourteenth. The quest for cheaper and more dependable sources of black pepper fuelled the Age of Discoveries; only after the discovery of the American Continents and of chilli pepper, called by the Spanish 'pimiento', employing their word for long pepper, did the popularity of long pepper fade away. Chilli peppers, some of which, when dried, are similar in shape and taste to long pepper, were easier to grow in a variety of locations more convenient to Europe. Today, long pepper is quite a rarity, but it still can be bought through more specialised food outlets.