
Durer, Fortuna 1502 engraving
Rota Fortuna
No mortal power may stay her spinning wheel.
The nations rise and fall by her decree.
None may foresee where she will set her heel:
She passes, and things pass.
Man’s mortal reason cannot encompass her
She rules her sphere as the other gods rule theirs.
Season by season her changes change her changes endlessly,
and those whose turn has come press on her so,
she must be swift by hard necessity.
Dante, Inferno VII 82-90
Fortune’s Wheel
From Wikipedia: The concept of Rota Fortuna arose in antiquity. The Wheel originally belonged to the Roman goddess Fortuna, whose name seems to derive from Vortumna, “she who revolves the year”. Fortuna eventually became Christianized: the Roman philosopher Boethius (d. 524) was a major source for the medieval view of the Wheel, writing about it in his Consolatio Philosophiae:
“I know how Fortune is ever most friendly and alluring to those whom she strives to deceive, until she overwhelms them with grief beyond bearing, by deserting them when least expected … Are you trying to stay the force of her turning wheel? Ah! dull-witted mortal, if Fortune begin to stay still, she is no longer Fortune.”
~ Boethius, The Consolation of Philosophy
The Wheel was widely used as an allegory in medieval literature and art to aid religious instruction. Though classically Fortune’s Wheel could be favourable and disadvantageous, medieval writers preferred to concentrate on the tragic aspect, dwelling on downfall of the mighty – serving to remind people of the temporality of earthly things.

From an edition of Boccaccio’s “De Casibus Virorum Illustrium” (Paris, 1467) MSS Hunter 371-372 (V.1.8-9). Image (vol. 1: folio 1r)
Fortune’s Wheel often turns up in medieval art, from manuscripts to the great Rose windows in many medieval cathedrals, which are based on the Wheel. Characteristically, it has four shelves, or stages of life, with four human figures, usually labeled on the left regnabo (I shall reign), on the top regno (I reign) and is usually crowned, descending on the right regnavi (I have reigned) and the lowly figure on the bottom is marked sum sine regno (I have no kingdom). For a largely illiterate population, visual imagery like this was a much more effective teaching method.

The Wheel of Fortune motif appears significantly in the Carmina Burana (or Burana Codex), over one thousand poems and songs — often profane in content — written by students and clergy in the early 13th century. Excerpts from two of the collection’s better known poems, “Fortuna Imperatrix Mundi (Fortune, Empress of the World)” and “Fortune Plango Vulnera (I Bemoan the Wounds of Fortune),” read:
O Fortuna O Fortune,
velut luna like the moon
statu variabilis, you are changeable,
semper crescis ever waxing
aut decrescis; and waning;
vita detestabilis hateful life
nunc obdurat first oppresses
et tunc curat and then soothes
ludo mentis aciem, as fancy takes it;
egestatem, poverty
potestatem and power
dissolvit ut glaciem. it melts them like ice.
Sors immanis Fate – monstrous
et inanis, and empty,
rota tu volubilis, you whirling wheel,
status malus, you are malevolent,
vana salus well-being is vain
semper dissolubilis, and always fades to nothing,
obumbrata shadowed
et velata and veiled
michi quoque niteris; you plague me too;
nunc per ludum now through the game
dorsum nudum I bring my bare back
fero tui sceleris. to your villainy.
Sors salutis Fate is against me
et virtutis in health
michi nunc contraria, and virtue,
est affectus driven on
et defectus and weighted down,
semper in angaria. always enslaved.
Hac in hora So at this hour
sine mora without delay
corde pulsum tangite; pluck the vibrating strings;
quod per sortem since Fate
sternit fortem, strikes down the string man,
mecum omnes plangite! everyone weep with me!
Fortune plango vulnera (I bemoan the wounds of Fortune)
Fortune plango vulnera I bemoan the wounds of Fortune
stillantibus ocellis with weeping eyes,
quod sua michi munera for the gifts she made me
subtrahit rebellis. she perversely takes away.
Verum est, quod legitur, It is written in truth,
fronte capillata, that she has a fine head of hair,
sed plerumque sequitur but, when it comes to seizing an opportunity
Occasio calvata. she is bald.
In Fortune solio On Fortune’s throne
sederam elatus, I used to sit raised up,
prosperitatis vario crowned with
flore coronatus; the many-coloured flowers of prosperity;
quicquid enim florui though I may have flourished
felix et beatus, happy and blessed,
nunc a summo corrui now I fall from the peak
gloria privatus. deprived of glory.
Fortune rota volvitur: The wheel of Fortune turns;
descendo minoratus; I go down, demeaned;
alter in altum tollitur; another is raised up;
nimis exaltatus far too high up
rex sedet in vertice sits the king at the summit -
caveat ruinam! let him fear ruin!
nam sub axe legimus for under the axis is written
Hecubam reginam. Queen Hecuba.

Codex Carmina Burana manuscript
A fantastic illustration of this theme is the great marbled floor in the Siena Cathedral:

For more information on this and related concepts, click here.