After spending all of May traipsing from one friend’s wedding to another, you might be unwilling to attend the vernal equinox party being hosted by your sister-in-law’s accountant. Your frantic search for an excuse to decline the invitation—” I’m having my hedgehog spayed”—would not surprise an ancient Roman, whose word for an invitation—invitatio—bears a striking resemblance to the Latin invitus, meaning unwilling. Whether or not these two Latin words are actually related to each other is uncertain, since the ultimate origins of both invitatio and invitus are unknown. However, if the two words do derive from a common source, then it suggests that invitations, in ancient times, were rather like subpoenas compelling an unwilling guest to attend some sort of ghastly formal occasion. In English, the word invitation appeared in the middle of the sixteenth century; prior to this, and dating back to the ninth century, an invitation was called a lathing, a word that likely derives from a Germanic source meaning willing.