Pope Benedict XVI, the former Cardinal Joseph Ratzinger who took office in 2005, said on Monday that he will resign on Feb. 28, the first pope to do so in six centuries.

The 85-year old pope said that after examining his conscience "before God, I have come to the certainty that my strengths, due to an advanced age, are longer suited to an adequate exercise” of his position as head of the world’s Roman Catholics.

In a statement in several languages, the pope said his "strength of mind and body” had "deteriorated in me to the extent that I have had to recognize my incapacity to adequately fulfill the ministry entrusted to me.”

The last pope to resign was Gregory XII, who left the papacy in 1415 to end what was known as the Western Schism among several competitors for the papacy.

Pope Benedict XVI was elected on April 19, 2005.