In the Chicago mayoral election of 1871, Joseph Medill defeated Republican/Democratic nominee Charles C. P. Holden by a landslide 46-point margin. Holden was president of the Common Council, and constructed the Landmark Holden Block in 1872. The election took place on November 7, a month after Chicago suffered the calamity of the Great Chicago Fire. The administration of the election was challenging because the majority of Chicago's voting records had been incinerated by the Great Chicago Fire, meaning that there were few resources to prevent individuals from voting more than once.