Holiness (style)
The title His Holiness is an official title or style referring to the Pope in the Catholic Church; this use can be traced back several hundred years. It has also been adopted as an official title for other leaders in a number of religious traditions. It is used to refer to Oriental Orthodox patriarchs, and used to refer to religious leaders in Islam, Buddhism, and Bon. Buddhist leaders referred to this way include the Dalai Lama, the Menri Trizin, among others; the Da'i al-Mutlaq of the Dawoodi Bohras is one example of a Muslim leader styled this way.
Buddhism and Bon
The English-language honorific "His Holiness" and the female version "Her Holiness" have commonly and very recently been used for religious leaders from other traditions, including Buddhism leaders such as the Thanlyin Mingyaung Sayadaw, Ashin Nandamalabhivamsa, Sangharaja in Thailand, Dalai Lama, the Gyalwa Karmapa, the Je Khenpo in Bhutan, and Shinso Ito of the Shinnyo-en branch of Shingon Buddhism. In the Bön tradition it is used for the Menri Trizin.Christianity
Catholic Church
His Holiness is the official style used to address the Pope.The full papal title, rarely used, is:
The best-known title, that of "Pope", does not appear in the official list of titles, but is commonly used in the titles of documents and appears, in abbreviated form, in their signatures as "PP", standing for Papa. The 2020 Annuario Pontificio lists all of his formal titles, except Bishop of Rome, as "historical titles".
It is customary when referring to popes to translate the regnal name into local languages.
In February 2013, the Holy See announced that former Pope Benedict XVI would retain the style "His Holiness" after resigning and becoming Pope Emeritus.
The term is sometimes abbreviated as "HH" or "H.H." when confusion with "His/Her Highness" is unlikely.