Themyscira first appeared as Paradise Island in All Star Comics #8 (Dec. 1941). It appeared as Themyscira itself in Wonder Woman (vol. 2) #1 (Feb. 1987). Themyscira is the island nation that is the place of origin of Wonder Woman and her sister Amazons. The island is named after the mythological city Themiscyra, the capital of the Amazon tribe in Greek mythology.
When Wonder Woman's homeland is first introduced in 1941, it is referred to as Paradise Island, a secret and hidden island inhabited by the Amazons of myth. The Amazons had grown tired of the evil ways of mankind in ancient Greece after being enslaved by Hercules and had separated themselves to this island where they could practice a peaceful way of life and cultivate their minds. With the island blessed by the Olympian Gods, no man is allowed to physically set foot on it. When United States Army intelligence officer Steve Trevor's plane crashes there during World War II, he is nursed back to health on the nearby Island of Healing by Princess Diana, daughter of the island's Queen Hippolyta. Diana soon competes against other Amazons to become Wonder Woman, the representative from Paradise island who will accompany Steve back to "Man's World" and aid in the fight against the Axis powers. It is established that all Amazons are adept at a discipline called "bullets and bracelets" in which they are able to deflect bullets fired at them using the metal cuffs on their wrists.
The 1987 relaunch of Wonder Woman establishes that the Amazons are the reincarnated souls of women slain throughout pre-history by men. Shaped from clay over 3,000 years previous and given new lives by five Olympian goddesses — Artemis, Athena, Demeter, Hestia, and Aphrodite — the Amazons are granted immortality, great physical strength, highly acute senses, beauty, wisdom, and love for one another. They are tasked to teach the merits of virtue, love, and equality to the men of "Patriarch’s World". They have founded the city-state of Themyscira in ancient Turkey, which is ruled by sisters Hippolyta and Antiope. Ares, the God of War and a chief opponent of the Amazons, manipulates his half brother Heracles to gather forces and attack Themyscira. Heracles subdues and ravages Hippolyta, and his forces succeed in ransacking Themyscira and making the Amazons their slaves. Hippolyta pleads with the goddesses for help. Athena agrees to aid the Amazons, but only if they do not go against their purpose of creation by seeking revenge. When they agree to her terms, Athena frees the Amazons from their chains. Once freed, however, the Amazons proceed to slaughter most of their captors. Antiope leads a force of Amazons off into Greece, seeking vengeance on Heracles. As decreed by the goddesses, Hippolyta leads the remaining Amazons to a remote island where, as penance for their failures as teachers, they become guardians of Doom’s Doorway, preventing the escape of the monsters beneath. Renaming the island paradise Themyscira after their fallen capital, the Amazons began their new lives, erecting buildings and monuments and perfecting their skills as artisans and warriors.
For centuries, the Amazons of Themyscira live in a perfect state of harmony with their surroundings. They know no racism, although many consider Antiope's Lost Tribe of Amazons as little more than savages. They do not think in terms of male gender; the word "policeman" is alien to them until Diana’s departure into the outside world. Homosexuality is completely accepted — while some Amazons are chaste, others have loving consorts. Their city is composed entirely of Greco-Roman architecture from 1200 BCE, and they wear Greek garb, togas, sandals, and period armor. The Amazons also all wear the Bracelets of Submission as constant reminders of their past, although only Diana is able to deflect bullets with them. They are fervently religious, worshipping their gods as living deities. Artemis is their primary goddess, and they worship her with a sacrifice of a deer. The Amazons celebrate their creation each year in a Feast of Five, remembering the goddesses who brought them to life.
Occasionally, the Nereides bring to the shores of Themyscira young infants who would have otherwise drowned in accidents. Called "sending forth", these infants are tutored spiritually in Amazonian ideals, and they are then sent back mystically to the place of their disappearance. Julia Kapatelis, Diana's first friend in Patriarch’s World, is one such infant.
Themyscira is presently located in the Bermuda Triangle, but possesses the magical ability to teleport to any location or time period its inhabitants desire.