Recent historical studies place the earliest Morris records in the time of Henry VI (c. 1448 payment of seven shillings to Morris dancers by the Goldsmiths' Company in London), as part of the court masques and entertainment. From the court it seems to have spread into popular entertainment, first in large houses, then to village celebrations, where it became associated with Church Ales and other seasonal festivities. In the 1500s Morris was also a European phenomenon with a version in other European Court entertainments. This would fit the close links between Morris Dancing and Mummers plays, as well as the use of baldrics and bells.
In Southern France. Northern Italy, Portugal, Spain and Adriatic states such as Croatia, there is a dance called the Mourisca, Moreška or Moresca which sometimes has comic characters and has a characteristic leg raising move (capers, hooklegs, galleys) and is supposed to represent confrontation between Moors and Christians. It in turn is said to derive from a Greek military dance - the Pyrrhica corrupted over time and parodied to become the dance of fools. The fact that the Pyrrhica (and Moreska) also uses swords may provide a link between Morris and the Sword Dance.
In some versions, there is dramatic action as well as a dance and the action tells a story based on mediterranean legends but involving Kings, good and evil, a maiden (king's daughter) or Moors and Turks and a slave - similar in a lot of ways to the Mummers. It is possible that crusaders came across the Moresca/Moreska/Morisco and brought the elements of it back to England. As soldiers, they would have acted all the parts as entertainment for each other, and when demonstrated back home, it became part of normal 'tradition' to have men dressed as women. The elements of conflict, blacking up, costumes, bells, swords, the characters all seem to fuse at this point in time and in this point in Europe.
In different cultures, the elements of the dance have separated or become isolated and are no longer linked together except by some vestige of forgotten origins. Where similar elements existed in the home country, incorporation and reinforcement seems to have taken place so that two or more traditions have fused and evolved into one - one local and others imported by crusaders, voyagers or itinerants - often returning armies.
Morris dancing is a confused and contentious subject. A spectacular (demonstration or display) dance rather than social, and widespread in the English midlands (Cotswolds) and Welsh Borders up to about 1850 where it suffered a rapid decline linked to the Industrial Revolution and disappearance of rural life. In the North West, it appears to have become incorporated into industrialised life. There is conjecture that the decline is also attributable to apathy amongst those made wealthy by industry and the marginalisation of 'quaint local customs'.
Morris is associated with a particular time of year (Cotswold = Spring, Border = Winter) such as May Day or Whit Monday and is based on the original (collected by Cecil Sharp) village traditions. The men could be persuaded out for fetes and fairs as well. Whether what Sharp collected was genuine or invented for him is another matter of conjecture. At least one tradition (Bidford) was invented. This reinforces the fact that a local tradition based on the calendar and pagan celebration pre-dated the arrival of European influences such as the Moricso.
There are several traditions of morris: Cotswold, Welsh Border and North West. Closely associated with Sword dancing (typically associated with the North East and Plough Monday) and other activities such as Furry dancing, Garland dancing, Molly Dancing, Mumming and Hoodening. Notice that the full complement of morris includes a sword bearer, hobby horse, King and Queen, Fool and other characters which suggest that Mumming and Morris were once part of the same tradition. The division of Morris into the categories known today was probably premature.
There is an argument that these fragments represent just one custom which was ritual and involved the slaughter of an animal ( e.g. Kirtlington, Abingdon, Abbotts Bromley). Kirtlington was reported (Esperance Book) to have a tradition of a lady who could not be touched during the day of dance. Accidental brushing would incur a fine. It is reported that latterly (1912) the lady was replaced with a lamb, although the conclusions drawn are perhaps spurious. However, such arguments are sometimes attributed to 19th Centuary romantic ideas about Paganism, and are dismissed as unfounded. Abingdon, for example, dances with a set of Ox Horns, which were reputedly won in a local skirmish between two opposing parts of the Town, following an Ox Roast, in 1700, rather than a ritual animal slaughter]. Swords came to be replaced by sticks and even handkerchiefs. There are striking examples of sword dancing, morris dancing and mummers as well as other associated customs all over Europe, many of them still bound together as one piece of theatre.
The names of the tunes and some of the dances lead to the supposition that the 'Morris Tradition' was an absorbing one which used widespread popular cultural references usually (but not always) deriving from campaigns, heros or characters of ridicule. Others seem just to be very popular songs of the time. Many of those we know are from the 18th century and this would fit with a restoration following the Commonwealth years:
Whether the dance remained the same and a new tune and title were adopted to celebrate some event is not now known, although several traditions have more than one identical dance (or almost) with a different name - often the name of the tune (e.g. Bampton Rose Tree / Banbury Bill / Country Gardens). A long time curiosity of a name, is Trunkles. Recent research proposes that this is either derived from a garment worn in the 16th / 17th century - Trunk Hose (see Henry VIII pictures) or from a Spanish word - Trunco meaning incomplete (truncated. It is possible of course that it is another case of the fusing of terms which existed at the same point in time. The Spanish origin would lend more weight to the Spanish Moresco derivation of the dances. The Esperence Morris Book records that old dancers called the dance known as Trunkles also as Trunk Hose and Old Trunco.
So it seems feasible that local regional customs and rituals dating from before the crusades - before the 10th century - became fused with imported dance and entertainment introduced by returning soldiers during the crusades (10th - 14th century) and well incorporated into the cultural landscape by the 15th and 16th century with many literary references. A decline in popularity in the 17th century was followed by a re-emergence in the 18th with a desire to celebrate 'Englishness' following the restration of the monarchy. At this point it seems to have taken on a different style and become more like the tradition we know today. Very few traditions surviveded with an unbroken run of activity and by the late 19th century, it had mostly died out again, only to be resurrected in the nick of time by Cecil Sharp and his colleagues from the memories of old men.
Is it for men only? Well there's a debate. Originally (as Sharp collected) there were only men dancing. As I conjecture above, this may have been either a false characteristic (passed on by all-male soldiers) or may have been a reinforcement of earlier all-male rituals. There are references to women's sides however and now mixed sides are common. There were more ancient references to womens' sides at Kirtlington for example and one tradition (Winster) has the two files of dancers called Ladies' Side and Mens' side - even if it's all men. A prime example of a ladies revival side is Betty Luptons Ladle Laikers from Harrogate.
There are societies you can join or be invited to. The oldest is the Morris Ring, the others of note are the Morris Federation and the Open Morris. There is The English Folk Song and Dance Society as well.
*Hop on to your right foot and lift your left leg and kick from the knee. Repeat with left foot / right leg. A bit like a Cossack standing up to dance.