Mendeleev is thought to be the youngest of either 11, 13, 14 or 17 siblings;] the exact number differs among sources] His father was a teacher of fine arts, politics and philosophy. Unfortunately for the family's financial well being, his father became blind and lost his teaching position. His mother was forced to work and she restarted her family's abandoned glass factory. At the age of 13, after the passing of his father and the destruction of his mother's factory by fire, Mendeleev attended the Gymnasium in Tobolsk.
Between 1859 and 1861, he worked on the capillarity of liquids and the workings of the spectroscope in Heidelberg. In late August 1861 he wrote his first book on the spectroscope. On 4 April 1862 he became engaged to Feozva Nikitichna Leshcheva, and they married on 27 April 1862 at Nikolaev Engineering Institute's church in Saint Petersburg (where he taught). Mendeleev became a professor at the Saint Petersburg Technological Institute and Saint Petersburg State University in 1864 and 1865, respectively. In 1865 he became Doctor of Science for his dissertation "On the Combinations of Water with Alcohol". He achieved tenure in 1867, and by 1871 had transformed Saint Petersburg into an internationally recognized center for chemistry research. In 1876, he became obsessed with Anna Ivanova Popova and began courting her; in 1881 he proposed to her and threatened suicide if she refused. His divorce from Leshcheva was finalized one month after he had married Popova (on 2