Mead is thought to be the world's oldest alcoholic drink, predating even agriculture! A reasonable suggestion is that our hunter-gatherer ancestors would have come across broken honeycomb, which would have filled with rainwater. Wild yeasts would then have fermented the exposed surface, producing a very weak alcoholic drink. Since this also predates historic records, it is somewhat difficult to prove, but it does make a certain amount of sense.
Ancient civilisations also drank mead, such as the Greeks, who called it hydromel, or "water-honey", which persists in many european languages. Dionysos / Bacchus was originally the god of mead and... "parties", and Aphrodite / Venus lent her name to it as an aphrodisiac. This changed when mead was usurped by wine. Due to agriculture, certain crops were plentiful, whereas honey was still relatively scarce, and was highly valued as a sweetener. This led to cheaper versions being created, which led to melomels, or fruit meads, and then to drinks without any honey in them at all. In Greece, the most popular were pyment (grape mead), hippocras (spiced grape mead), and then wine - due to the high sugar content of grapes. Over time, the yeast was also bred to produce higher alcohol drinks. As honey is found worldwide, but fruit varies, there are a variety of melomels, and non-honey drinks worldwide.
In the UK, some of the popular melomels were red mead (redcurrant), black mead (blackcurrant), morat (mulberry), and cyser (apple), the last of which eventually became cider. The other fruits have lower sugar content, and thus produce lower alcohol drinks, hence why only cider became highly popular. Due to the high price, mead was the drink of kings, and then the church. Monks were the church's beekeepers, and as such, had ready access to honey, hence the image of Friar Tuck. On the other hand, alcohol is a useful solvent, and monks often infused their mead with medicinal herbs, with the sweet taste hiding the bitterness of certain herbs. Whereas the Greeks called such a drink hippocras (after Hippocrates, the "father of medicine"), we took the British word "metheglyn", meaning "medical liquour". The practice was continued with ale, where the combination of herbs was called a gruit (e.g. the gruit of beer is hops). Ale itself was not derived from an intermediate with mead, however a back-formation was invented, called "braggart" (barley-water mead). There are several mead cocktails that have since been invented since, some of which were supposed to be sleeping aids. Nowadays, (most of us) know better; current metheglyns have culinary herbs in them for flavouring only, and other compounds are safer without being added to alcohol. (If you really want to know, ethanol competitively inhibits the cytochrome P450 oxidase system, which will slow the breakdown of other xenobiotics, making the dosage inaccurate. It can also potentially acetylate reactive groups on various drug molecules).
One of the interesting properties of mead as a drink is that because honey is about 80% sugar and because it requires diluting, it can be made to be any kind of strength, depending on the yeast used. Combined with the fact that honey takes on taste characteristics of the kinds of nectar used to make it, and that herbs and fruit can be added to it, it is possibly the most diverse type of drink. For example, it is possible to make a 20% red mead without distilling, but not a redcurrant wine. It is even possible to make a sweet 20% red mead. High alcohol meads are called sack, (possibly named after sake) and were present during the mediaeval period. Unfortunately, distilling mead tends to destroy the delicate tastes in honey, and can lead to a "cooked" taste with fruit. This can be circumvented by ice-distilling (like making applejack), but this is not particularly traditional.
Mead has played an important part in both religious ceremonies, and social gatherings throughout the ages. In our own history, we saxons used to gather in mead halls for important events and feasts, and our pre-christian religion talks of the blood of Kvasir as being the sweetest mead, granting knowledge and the gift of poetry. It is a shame that mead has played a huge role in human culture for such a long time, yet now few people seem to know what it even is! Don't settle for the modern, cheap mead-substitutes, like wine, beer and cider, and try mead!
The old English runes (from the elder futhorc) on the welcome page say "Waes Hael", which means "(I) wish (you) health". The reply is "Drinc Hael", "(I) drink (your) health", followed by drinking mead. The modern wessex pronunciation is "wassail", and basically means "cheers".