Career
Originally trained in mathematics, geography and theology, in 1874 Zeller became Director of the Seminary in Markgröningen and a girls" orphanage. The following year, on 16 March 1883, he delivered a short account of his congruence relation (Zeller"s congruence), which was published in the society"s journal. He was later awarded the Order of Friedrich, First Class, and the Ritterkreuz of Württemberg.
He retired in 1898, and died in the following summer.
