At the time of Ignatius Jacob II's death, in 1871, Peter was staying in Constantinople and could not travel to Mardin for the patriarchal election. However, the synod unanimously elected him as patriarch. At first he declined the position, but under continuous persuasion Peter was consecrated Patriarch on 16 June 1872 at the Monastery of Mor Hananyo, upon which he assumed the Patriarchal name Ignatius.