Tyche was the presiding tutelary deity who governed the fortune and prosperity of a city, its destiny. In Classical Greek mythology, she is usually the daughter of the Titans Tethys and Oceanus, or sometimes Zeus, and at this time served to bring positive messages to people, relating to external events outside their control.
Polychrome marble statue depicting Tyche holding the infant Plutus in her arms, 2nd century AD, Istanbul Archaeological Museum
Tyche on the reverse of this base metal coin by Gordian III (r. 238 – 244 AD)
The Three Tychai, c. 160 AD, Louvre Museum
The remains of a Greek temple of Tyche, Olba
Fortuna is the goddess of fortune and the personification of luck in Roman religion who, largely thanks to the Late Antique author Boethius, remained popular through the Middle Ages until at least the Renaissance. The blindfolded depiction of her is still an important figure in many aspects of today's Italian culture, where the dichotomy fortuna / sfortuna plays a prominent role in everyday social life, also represented by the very common refrain "La [dea] fortuna è cieca".
Fortuna
Fortuna governs the circle of the four stages of life, the Wheel of Fortune, in a manuscript of Carmina Burana
The humiliation of Emperor Valerian by king Shapur I of Persia (260) passed into European cultural memory as an instance of the reversals of Fortuna. In Hans Holbein's pen-and-ink drawing (1521), the universal lesson is brought home by its contemporary setting.
Fortuna lightly balances the orb of sovereignty between thumb and finger in a Dutch painting of ca 1530 (Musée des Beaux-Arts de Strasbourg)