Maria of Tver

Maria Borisovna of Tver (Мария Борисовна; 1442 – 22 April 1467) was the grand princess of Moscow as the first wife of Ivan III from 1462 until her death in 1467. She was the daughter of Boris of Tver.

Biography
When Vasili II, Ivan III's father, was getting ready to attack Dmitry Shemyaka, he found an ally in the person of Boris of Tver. The two decided to seal the alliance by arranging a betrothal between the future Ivan III and Maria of Tver in 1452. It appears that she died from poisoning in 1467. However, if one is to believe Joseph Volotsky, she had been suffering from "infirmity" since childhood. She gave birth to Ivan the Young in 1458.