Kostroma

Kostroma is the goddess of spring, fertility and summer in Eastern Slavic Mythology. She was the patroness of lovers. Kostroma is a daughter of Simargl and Kupalnitsa. Her brother and husband is Kupalo.

Myths & Legends
According to the myth, Kupalo and Kostroma were twins. Their parents were Simargl, the god of fire, and Kupalnitsa, goddess of night. Once, Kostroma and Kupalo ran into a field to listen to songs of birds Sirin, the bird of sorrow, and Alkonost, the bird of joy. Both birds, especially Sirin, were dangerous. The one who listened to the singing of Sirin, forever went into the Nav, the world of the dead. Kostroma listened to the singing of Alkonost, while Kupalo listened to the song of Sirin. And then, by the order of Chernobog, Sirin and gusi-lebedi (The Magic Swan Geese) stole Kupalo and carried him into the Nav.

Many years later, one day, Kostroma walked the shore of the river Smorodina and made a wreath. She boasted that the wind would not blown wreath off her head. According to the belief, it meant that she would not marry. This boast was not approved by the gods. Perun caused a storm, and the winds of Stribog blew Kostroma's wreath into the water. It was picked up by Kupalo, who was near by in the boat. According to the Slavic customs, the one who picked up the wreath must necessarily marry the girl who made it. Kupalo and Kostroma fell in love and shortly were married without any knowledge that they were brother and sister.

After the wedding, the gods told them the truth. That is why Kupalo and Kostroma committed suicide. Kupalo has jumped into the fire and died, while Kostroma ran to the forest, threw herself into the lake and drowned. But she did not die completely: she became a mavka, a female water spirit. Walking around that lake, she charmed the men she met on her path and dragged them into the water abyss. She mistook them for Kupalo, and found out that the caught young man was not her lover only when he had already drowned.

And then, the gods repented, realizing that their revenge was too cruel. But to give Kupala and Kostroma the human body again was impossible, and they turned them into the flower with yellow and blue petals, in which the fiery yellow color was the color of Kupala, and the blue one, like the waters of the forest lake, was the color of Kostroma. The Slavs gave the name Kupalo-da-Mavka (Kupalo-and-Mavka) to the flower. Later, in the time of Christianization in Rus, the flower was renamed to the Ivan-da-Marya (Ivan-and-Marya).

Variations
In another version of the myth, Kostroma and Kupalo committed suicide in a slightly different way: they took each other's hands and jumped into the river from the cliff. This version also does not include Alkonost, and Sirin is present alone in it.

The name of the river also changes depending on the version: sometimes it is called the Volga, sometimes the Smorodina, and sometimes the Ra; it is known that Ra is the ancient name of the Volga.