In ancient Greek city cults, Tyche (Τύχη, meaning "luck" in Greek, Roman equivalent: Fortuna) was the presiding tutelary deity that governed the fortune and prosperity of a city, its destiny.

Increasingly during the Hellenistic period, cities venerated their own specific iconic version of Tyche, wearing a mural crown (a crown like the walls of the city).

The Greek historian Polybius believed that when no cause can be discovered to events such as floods, drought or frosts then the cause of these events may be fairly attributed to Tyche.[1]

Stylianos Spyridakis [2] concisely expressed Tyche's appeal in a Hellenistic world of arbitrary violence and unmeaning reverses: "In the turbulent years of the Epigoni of Alexander, an awareness of the instability of human affairs led people to believe that Tyche, the blind mistress of Fortune, governed mankind with an inconstancy which explained the vicissitudes of the time."[3]

In literature, she might be given various genealogies, as a daughter of Hermes and Aphrodite, or considered as one of the Oceanids, daughters of Oceanus and Tethys, or of Zeus.[4] She was connected with Nemesis[5] and Agathos Daimon ("good spirit").

She was uniquely venerated at Itanos in Crete, as Tyche Protogeneia, linked with the Athenian Protogeneia ("firstborn"), daughter of Erechtheus, whose self-sacrifice saved the city.[6]

She had temples at Caesarea Maritima, Antioch, Alexandria and Constantinople. In Alexandria the Tychaeon, the temple of Tyche, was described by Libanius as one of the most magnificent of the entire Hellenistic world.[7]

Tyche appears on many coins of the Hellenistic period in the three centuries before the Christian era, especially from cities in the Aegean. Unpredictable turns of fortune drive the complicated plotlines of Hellenistic Romances, such as Leucippe and Clitophon or Daphnis and Chloe. She experienced a resurgence in another era of uneasy change, the final days of publicly-sanctioned Paganism, between the late-fourth-century emperors Julian and Theodosius I who definitively closed the temples. The effectiveness of her capricious power even achieved respectability in philosophical circles during that generation, though among poets it was a commonplace to revile her for a fickle harlot.[8]

In medieval art, she was depicted as carrying a cornucopia, an emblematic ship's rudder, and the wheel of fortune, or she may stand on the wheel, presiding over the entire circle of fate.

The constellation of Virgo is sometimes identified as the heavenly figure of Tyche,[9] as well as other goddesses such as Demeter and Astraea.

From: Wiki
In Greek mythology, Tyche was the goddess of fortune. In addition to her role as the goddess of fortune, however, Tyche was also the personification of a concept - tyche - that both intrigued and inspired ancient Greek poets, philosophers, writers, and artists. This concept was variously interpreted over the years, and represented not only fortune, but also luck, success, or even chance.

Tyche is listed as one of the Oceanids (daughters of the Titans Tethys and Okeanos) in the Theogony of Hesiod. Indeed, paired with her sister Eudora, she and her sibling together represent a combination of Bounty and Luck according to the Oxford Classical Dictionary. This same source also indicates that Tyche appears again as a personification associated with Bounty in the Homeric Hymn to Demeter.

It is also worth noting that Tyche was a highly regarded goddess in many of the cities of ancient Greece. She was worshipped and honored as a sort of patron deity of luck or fortune in these cities. Works of art were created to celebrate the power and prestige of this important goddess, and two of the most famous examples of ancient images of Tyche were the statue of Agathe Tyche (Good Fortune) by Praxiteles and the Tyche of Antioch by Eutychides. The Hellenistic Tyche of Antioch, in fact, was so popular that it became the prototype and standard upon which other images of the goddess were based.

Tyche was called Fortuna in Roman mythology.

From: here
Blessing: Tyche is the giver of good fortune and the bringer of evil, a Goddess if whimsy, and an emblem of inescapable destiny. She teaches the paradoxical message that life is essentially a game of dice, determined by chance, and that nothing is ever set in stone. No matter how certain we are that something will happen, there’s always an element of chance to it, and the unexpected may turn out to be what happens. Instead of submission to Fate, Tyche encourages her followers to take things into their own hands, and make their own destiny. Sometimes we succeed, sometimes we don’t – it’s all up to chance.

Epithets: Agathe (the Good), Megale (Great), Soteira (Savior), Fortuna (Fortune)

Equated with: Fortuna, Isis, Demeter, Hermouthis, Hariti

Associations: Serpent, wheel, globe, cornucopia, turreted crown, coin

From: Neos Alexandria
Orphic Hymn 72 To Tykhe, Fumigation from Frankincense. Approach, queen Tykhe, with propitious mind and rich abundance, to my prayer inclined: placid and gentle, mighty named, imperial Artemis, born of Eubouleos famed, mankind’s unconquered endless praise is thine, sepulchral, widely wandering power divine! In thee our various mortal life is found, and come from thee in copious wealth abound; while others mourn thy hand averse to bless, in all the bitterness of deep distress. Be present, Goddess, to thy votaries kind, and give abundance with benignant mind.


From: Orphic Hymn 72
Tykhe, beginning and end for mankind, you sit in Sophia’s seat and give honour to mortal deeds; from you comes more good than evil, grace shines about your gold wing, and what the scale of your balance gives is the happiest; you see a way out of the impasse in troubles, and you bring bright light in darkness, you most excellent of gods.

From: Greek Lyric V Anonymous, Fragments 1019 (from Stobaeus, Anthology)
TYKHE was the goddess or spirit of fortune, chance, providence and fate. She was usually honoured in a more favourable light as Eutykhia, goddess of good fortune, luck, success and prosperity.

Tykhe was represented with different attributes. Holding a rudder, she was conceived as the divinity guiding and conducting the affairs of the world, and in this respect she was called one of the Moirai (Fates); with a ball she represented the varying unsteadiness of fortune--unsteady and capable of rolling in any direction; with Ploutos or the horn of Amalthea, she was the symbol of the plentiful gifts of fortune.

Nemesis (Fair Distribution) was cautiously regarded as the downside of Tykhe, one who provided a check on extravagant favours conferred by fortune. The pair were often depicted as companions in Greek vase painting. In the vase (right) Nemesis (Indignation) with her arm around Tykhe (Fortune) points an accusing fingure at Helene, who Aphrodite has persuaded to elope with Paris.

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ENCYCLOPEDIA

TYCHE (Tuchê). 1. The personification of chance or luck, the Fortuna of the Romans, is called by Pindar (Ol. xii. init.) a daughter of Zeus the Liberator. She was represented with different attributes. With a rudder, she was conceived as the divinity guiding and conducting the affairs of the world, and in this respect she is called one of the Moerae (Paus. vii. 26. § 3; Pind. Fragm. 75, ed. Heyne); with a ball she represents the varying unsteadiness of fortune; with Plutos or the horn of Amalthea, she was the symbol of the plentiful gifts of fortune. (Artemid. ii. 37.) Tyche was worshipped at Pharae in Messenia (Paus. iv. 30. § 2); at Smyrna, where her statue, the work of Bupalus, held with one hand a globe on her head, and in the other carried the horn of Amalthea (iv. 30. § 4); in the arx of Sicyon (ii. 7. § 5); at Aegeira in Achaia, where she was represented with the horn of Amalthea and a winged Eros by her side (vii. 26. § 3; comp. Plut. De Fort. Rom. 4; Arnob. adv. Gent. vi. 25); in Elis (Paus. vi. 25. § 4); at Thebes (ix. 16. § 1); at Lebadeia, together with agathos daimôn (ix. 39. § 4); at Olympia (v. 15. § 4), and Athens. (Aelian, V. H. ix. 39; comp. Fortuna.) 2. A nymph, one of the playmates of Persephone. (Hom. Hymn. in Cer. 421.) 3. One of the daughters of Oceanus. (Hes. Theog. 360.)

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TYKHE was widely worshipped as the guardian spirit of a city's good fortune. As such she was usually depicted crowned with the turrets of a city-wall and holding a cornucopia (horn of plenty) brimming with the fruits of the earth.

Photographs of several Tykhe cult statues are linked to below. In most of her representations she is barely distinguishable from Demeter: the crown, cornucopia and Ploutos-child being common attributes of both goddesses. Indeed Tykhe (Lady Fortune) often appears to be merely an aspect of the goddess Demeter.

CULT TITLES OF TYKHE

Tykhe had a few cult titles such as Agathe Tykhe (Good Fortune) and Tykhe Akraie (Of the Height) describing the location of one of her shrines:--

Greek Name Transliteration Latin Spelling

Translation
Agathê Tykhê Agatha Tyche Good Fortune
Eutykhia Eutychia Good Fortune, Luck
Akraiê Acraea Of the Heights
Automatia Automatia Self-Animate
Meilikhios Melichius Gentle, Soothing
Sôtêria Soteria Saviour

From: Theoi
Also see:
Fortuna {Goddess of the Week}
Olympian Ode 12 by Pindar
Three Hymns by Isidorus
Hymn to Agathe Tykhe by Rebecca Buchanan
To Tykhe-Fortuna by Amanda Sioux Blake
Theoi: Cult of Tykhe
Theoi: Tykhe (has more info)
Modern hymns to her (2 of them)
Article/essay