The first wife of Einstein, Mileva Mari and mother of his two sons and Einstein separated and divorced. Though Mileva had custody of their children. No one can deny relationship and care of Einstein being a father. He guide, teach and play whenever together with his sons.
When Einstein spent time making little toys for his baby son, such as a cable car constructed from match boxes and string.
Hans Albert himself told when he was an adult.
Hans Albert recalled his memory with his father
Tanner a student told about a visit
Einstein also expressed his delight that his son has the interest in geometry and wrote him.
Einstein wrote to his sons for their personal Hygiene.
Einstein showed his care for his son Hans Albert.
Einstein sent Mari a note of thanks:
He wrote Elsa.
Eduard asked why he was so famous; He gave a beautiful example to elaborate to his child.
His Younger son Eduard was a patient of mental illness and he was worried about him very much.