Fessonia, or probably more properly, Fessona, is a Roman Goddess Who aids the weary. Not a whole lot is known of Her besides Her name, which is assumed to be from Latin fessus, meaning "weary", "tired", "exhausted", or "worn out"; the only ancient mention of Her is in Augustine's 5th century CE City of God, where he ticks off a list of minor Deities in order to mock the Pagan ways that were competition for his Christianity. (And yes, he comes off like a right royal bastard, if you ask me.)

She is also mentioned by the 16th century Flemish cartographer Abraham Ortelius, considered the father of the modern atlas, and a guy who it seems knew his Augustine. Apparently She came to him in a dream, and inspired him to draw the famous Vale of Tempe in Thessaly, Greece, not far from Mount Olympos, thought to be an especially idyllic and tranquil place where the weary might find true rest. Of course the real (not the poetic) beauty of the Vale of Tempe is of a rather more rugged sort, with dramatic cliffs for part of its way, said in legend to have been split open by a forceful jab from Poseidon's trident; but, well, Ortelius probably didn't know that.

Fessus can also be used of illness, to mean "sick", "feeble", or "infirm", so it is not too much of a stretch to guess that Fessonia may have been invoked to aid healing in the case of illness, and to ward off the weariness being sick can cause. Though I suppose that is fairly circular, as weariness can both cause and be the result of illness. At any rate, as the Goddess of weariness, or as the Goddess Who was in charge of weariness, it is probably also not too much to assume that in parallel with other Deities of sickness such as Febris Fessonia was thought to both cause and cure weariness. Which, to string it along a little further, could make Her the Goddess of bed-rest.

Conjecture, I know. But hey, I'm tired.