Ronald Hutton. Stations of the Sun. Oxford University Press: New York, 1996.
This book is so full of awesome.
The earliest English reference to "bringing in the May" dates to 1240, where a bishop in Lincoln was complaining about it. The fourteenth century saw many literary references to it, including Chaucer (mostly the gathering of flowers and making of garlands) and Malory (Queen Guinevere's Maying). In Scotland, William Dunbar wrote:
every one of thir, in grene arrayit,Henry VIII and Catherine of Aragon went out to feast in the woods of Shooter's Hill on May Day in 1515; Elizabeth apparently danced at country houses on May Day.
On harp and lute full mirrely the play it,
And sang ballatis with michty nottis cleir;
Ladies to danss full sobirly assayit,
Endlang the lusty rever so they mayit.
Have I mentioned all of these factoids come with citations? Awesome.
And interestingly: "The behaviour of young people on May Eve and May Day had thus become a cliche of scandal and of titillation alike [in period]. It took until the late twentieth century, and the patient labours of demographic historians, to reveal that there was in fact no rise in the number of pregnancies at this season, in or out of marriage. The boom in conceptions came later in the summer. In practice early modern people seem to have found the night of 30 April generally too chilly, and the woods generally too damp."
The first solid reference to a maypole comes in a mid-fourteenth century Welsh poem by Gryffydd ap Adda ap Dafydd; it describes a tall birch as a focal point for festivities. Chaucer's poem Chaunce of the Dice refers to a permanent maypole at Cornhill in London. (A review of this book by the journal Folklore points out that this poem's attribution to Chaucer is apocryphal; but it is still an early mention.)
He finds no evidence that the pole was regarded either as a fertility symbol or as a world-tree by the people who danced around it.
He comments on Stubbes account, remarking that this was an exceedingly large pole and procession, perhaps as might be seen in London but not in any small village. There is another example of flags and streamers decorating the top of a pole in the 1560s in Plymouth, and of a minstrel hired to play before one in Leicestershire market from 1586-1593. No ribbon dancing was found before the nineteenth century, but dancing or dancing games with kissing were popular. Hutton quotes poet Nicholas Breton in 1618: "the may-pole, where the young folk smiling kiss at every turning."