[1] His doctorate dissertation, De Arnulfo Francorum rege (Berlin, 1852), was a notable essay among historians.
This was an official recognition of Dümmler's leading position among German historians.
In conjunction with Wattenbach, he completed the Monumenta Alcuiniana (Berlin, 1873), which had been begun by Philipp Jaffé, and with Rudolf Köpke, he wrote Kaiser Otto der Grosse (Leipzig, 1876).
[3] He also edited the first and second volumes of the "Poetae Latini aevi Carolini" for the Monumenta Germaniae Historica (Berlin, 1881–84).
[2][4] His son, Georg Ferdinand Dümmler (1859–1896), an archaeologist and philologist, was professor at the University of Basel from 1890 until his death on 15 November 1896, aged 37.