Who is Klara Polzl from Hitler and what is their importance?

Klara Polzl was the mother of Adolf Hitler, she was born in 1860 and died in 1902. Klara was more than twenty years younger than Hitler's father, Alois Hitler. She was pregnant with their first child before their marriage and Hitler was the fourth of six children born of that union. Klara lost her three oldest children when each was younger than three and that likely made her more protective of her surviving children, including Hitler, his younger sister Paula and his younger brother, Edmund.