They were marryed: well that daye was past with dauncing and Honney moone it was for a moneth after.
This was written by a writer and playwright Robert Greene (1558-1592). There was an earlier entry. It was yet but hony moone. This is from John Heywood's A dialogue conteinyng the nomber in effect of all the prouerbes in the englishe tongue, 1st edition, 1546. It is likely that this is also the familiar use of "honeymoon." We simply don't know when the phrase was first used. The common notion in cases like this is to say "Well, it must have been around for awhile." Fine, but for how long? Marriages are pretty common, and writing about them is also pretty common, so not finding an earlier reference to a couple embarking on the "honey moon" should give us reason to pause in our assumptions.
Another theory about the origin is that newly married couples were gifted a month's worth of honey mead. I like it. Women were the brewers in the household, since they could stay in and work while the men farmed. A gift like this would allow her time to follow other home-making (baby-making) pursuits. I wish I could find a source for this.
Old English had a term, hony moone, but it refers to a moon during June. Now, perhaps they associated June with marriage, the way the Romans did (June being named after Juno and Juno being the goddess of marriages, and all that), but unless June was the only month that Anglo-Saxons got married...
Speaking of the Northern European types, I found one website that claimed the Norse word hjunottsmanathr meant honeymoon. I can see the resemblance, since "hjuno" looks like "Juno" and would be pronounced "hyuno" and sound a little like "honey." But...no. hjunott means "in hiding" and referred to spending time alone and away from others, celebrating your newly wedded bliss.