Zakka was a member of different Eastern and Western Academies and authored a number of books on Christian education, theology, history, and culture in Syriac and the Arabic and English languages. He established a monastic seminary, the Monastery of St. Ephrem The Syrian, at Marrat Saidnaya. Inaugurated on 14 September 1996, this Monastery forms part of a larger project which will include different centers and facilities. During the visit of Pope John Paul II to Syria in 2001, the Pope paid a historic visit to Patriarch Zakka in Damascus. The meeting took place on 6 May in St. George's Patriarchal Cathedral at Bab Touma. The following year, Iwas installed Mor Dionysius Thomas, the president of the Episcopal Synod of Indian Church, as the Catholicos of India with the title Mor Baselios Thomas I. Celebrations were held for the Patriarch's Silver Jubilee on 14 September 2005.