occur and they noticed the change in taste and effect. Yeasts would settle on the mixture and rapidly consume the oxygen in the mixture. The low oxygen would was a significant consequence of allowing the yeast to digest sugars by anaerobic respiration. The yeast would release ethanol (alcohol) and carbon dioxide as by-products and, hence, beer was born. The earliest archaeological evidence of fermentation consists of 13,000-year-old residues of a beer with the consistency of gruel, used by the semi-nomadic Natufians for ritual feasting, at the Raqefet Cave in the Carmel Mountains near Haifa in Israel. The first written records of brewing come from Mesopotamia (ancient Iraq), with the oldest in the Sumerian language from approximately 4,000 BC. These include early evidence of beer in the 3,900-year-old Sumerian poem honoring Ninkasi, the patron goddess of brewing, which contains the oldest surviving beer recipe, describing the production of beer from barley via bread. Approximately 5,000 years ago, workers in the city of Uruk were paid by their employers in beer. Beer is also mentioned in the Epic of Gilgamesh, in which the 'wild man' Enkidu is given beer to drink. "... he ate until he was full, drank seven pitchers of beer, his heart grew light, his face glowed and he sang out with joy." In February 2019, archaeologists from Mola Headland Infrastructure and experts from Highways England found evidence of first Iron Age beer dated back over 2,000 years during road works in Cambridgeshire. In February 2021, archaeologists found a 5,000-old beer factory in Abydos, Egypt, dating back to the reign of King Narmer, Early Dynastic Period. "It's a well-known fact that ancient populations used the beer-making process to purify water and create a safe source of hydration, but this is potentially the earliest physical evidence of that process taking place in the UK", said archaeologist Steve Sherlock. Confirmed written evidence of ancient beer production in Armenia can be obtained from Xenophon in his work Anabasis (5th century BC) when he was in one of the ancient Armenian villages in which he wrote: Beer became vital to all the grain-growing civilizations of Eurasian and North African antiquity, including Egypt—so much so that in 1868 James Death put forward a theory in The Beer of the Bible that the manna from heaven that God gave the Israelites was a bread-based, porridge-like beer called wusa. These beers were often thick, more of