Countess Johanna of Hainaut was a noblewoman born in the early 14th century, known for her significant role in the political landscape of medieval Europe. She was the daughter of Count William I of Hainaut and Countess Jeanne of Valois, which connected her to influential families in the region. Johanna's marriage to Count William II of Holland further strengthened alliances between noble houses. Throughout her life, Johanna was involved in various political matters, including the governance of Holland and Hainaut. Her lineage and marriage made her a key figure in the struggles for power during a time marked by territorial disputes and shifting allegiances among European nobility.