The legend of the lovers of Teruel tells the love story between two young women from Teruel, Isabel de Segura and Juan Martínez de Marcilla (also identified as Diego de Marcilla), known from Baroque theatre recreations as Diego. Since 1996 in Teruel (Spain), as a reminder of the tradition, a dramatised medieval re-enactment of The Marriage of Isabel de Segura has been held.

Legend has it that once upon a time in Teruel during the 13th century, there was a rich merchant who had a very beautiful daughter. The girl, named Isabel de Segura, and a poor but honest boy named Diego de Marcilla, met one day in the market and fell deeply in love. The young people loved each other very much. Diego confessed to her that he wished to take her as his wife. She replied that her desire was the same, but that she knew she would never do so without her parents' approval. Unfortunately, although Diego Marcilla was a fine young man, he possessed neither wealth nor property. Diego told the maiden that, as his father only despised him for lack of money, if she would wait five years for him, he would be willing to go out and seek his fortune wherever it was necessary in order to earn money and make himself worthy of marriage. She promised him.

Fighting in the Reconquista, after five years he earned one hundred thousand sueldos. During this time Isabella was pestered by her father to take a husband. She managed to prevent him from marrying her, telling him that she had taken a vow of virginity until she was twenty years old and maintaining that women should not marry until they could and knew how to run their own household. When she was five years old, her father said to her, "Daughter, it is my wish that you should marry. And when she saw that the five years were about to expire, and her bridegroom did not appear or give an account of himself, she ended up believing that he was dead. Her father immediately arranged for her to marry a rich suitor. That same day, however, Diego de Marcilla, who had suffered all sorts of mishaps, returned.

That night, Diego managed to enter unseen into the bedroom where the couple slept, and gently awoke her, begging her, "Kiss me, for I am dying," and she answered him in pain, "God willing I should fail my husband; by the passion of Jesus Christ I beseech you to seek another, that you make no account of me, for if it has not pleased God, it pleases me not. Again he said, "Kiss me, I am dying. She said, "I will not. Then he fell down dead.

She, who could see him as if it were daylight because of the great light in the room, began to tremble and woke her husband, saying that he was snoring so loudly that he was afraid to tell her something. And he told a joke. She said she wanted to tell another. And she told him what had happened and how with a sigh Diego had died. And her husband said: "Oh, wicked woman, why didn't you kiss him? She replied: "So as not to disrespect my husband". "Certainly," said he, "you are worthy of praise". He, all upset, stood up and did not know what to do. He said, "If the people know that he is dead here, they will say that I have killed him, and I shall be put to great trouble." They agreed to make an effort and took him to his father's house. They did so with great eagerness and were heard by no one. It came into the young girl's mind how much Diego loved her and how much he had done for her, and that because she did not want to kiss him she had died. She agreed to go and kiss him before he was buried; she went to the church of San Pedro, where he was buried. The honest women stood up for her. She cared for nothing else but to go to the dead man. She uncovered his face by pulling aside the shroud, and kissed him so hard that he died there. The people who saw that she, who was not a relative, was thus lying on the dead man, went to tell her to get rid of him, but they saw that she was dead. The husband told the story to all those who were present, as she had told him. They agreed to bury them in one grave together forever.