The third child of the family, who went on to become a famous mathematician, was Harald Bohr who was two years younger than Niels.

Two years later Niels was born on his mother's 25 th birthday in the same stately home, Ellen again having returned to her mother's house for the birth of her child. Ellen's mother had continued to live in this house after her husband David Adler died in 1878 and Ellen had gone back to her mother's home to have her child. The eldest was Jenny born in 1883 in the mansion which David Adler had owned opposite Christiansborg Castle where the Danish Parliament sat.

Late in the same year he married Ellen, who was the daughter of David Adler, a Jewish politician with a high standing in Danish political and commercial life. Christian Bohr was awarded a doctorate in physiology from the University of Copenhagen in 1880 and in 1881 he became a Privatdozent at the university.

Biography Niels Bohr's father was Christian Bohr and his mother was Ellen Adler.