Passage: Beer was spread through Europe by Germanic and Celtic tribes as far back as 3000 BC, and it was mainly brewed on a domestic scale. The product that the early Europeans drank might not be recognised as beer by most people today. Alongside the basic starch source, the early European beers might contain fruits, honey, numerous types of plants, spices and other substances such as narcotic herbs. What they did not contain was hops, as that was a later addition, first mentioned in Europe around 822 by a Carolingian Abbot and again in 1067 by abbess Hildegard of Bingen.In 1516, William IV, Duke of Bavaria, adopted the Reinheitsgebot (purity law), perhaps the oldest food-quality regulation still in use in the 21st century, according to which the only allowed ingredients of beer are water, hops and barley-malt. Beer produced before the Industrial Revolution continued to be made and sold on a domestic scale, although by the 7th century AD, beer was also being produced and sold by European monasteries. During the Industrial Revolution, the production of beer moved from artisanal manufacture to industrial manufacture, and domestic manufacture ceased to be significant by the end of the 19th century. The development of hydrometers and thermometers changed brewing by allowing the brewer more control of the process and greater knowledge of the results.

Question: What are examples of common ingredients in early European beers?
fruits, honey, numerous types of plants, spices and other substances such as narcotic herbs