and Sunday should be observed. Zara Yaqob was successful in persuading two recently-arrived Egyptian Abuna, Mikael and Gabriel, into accepting a compromise aimed at restoring harmony with the House of Ewostatewos, as the followers of Ewostatewos were known. At the same time, he made efforts to pacify the House of Ewostatewos. While the Ewostathians were won over to the compromise by 1442, the two Abuns agreed to the compromise only at the Council of Debre Mitmaq in Tegulet (1450). Zara Yaqob also continued as the defender of the Patriarch of Alexandria. When he heard in 1441 of the destruction of the Egyptian monastery of Debre Mitmaq by Sayf ad-Din Jaqmaq, the Mamluk sultan of Egypt, he called for a period of mourning, then sent a letter of strong protest to the Sultan. He reminded Jaqmaq that he had Muslim subjects whom he treated fairly, and warned that he had the power to divert the Nile, but refrained from doing so for the human suffering it would cause. Jaqmaq responded with gifts to appease Zara Yaqob's anger, but refused to rebuild the Coptic churches he had destroyed. According to Richard Pankhurst, Zara Yaqob was also "reputedly an author of renown", having contributed to Ethiopian literature as many as three important theological works. One was Mahsafa Berha "The Book of Light", an exposition of his ecclesiastical reforms and a defence of his religious beliefs; the others were Mahsafa Milad "The Book of Nativity" and Mahsafa Selassie "The Book of the Trinity". Foreign affairs Zara Yaqob sent delegates to the Council of Florence in 1441, and established ties with the Holy See and Western Christianity. They were confused when council prelates insisted on calling their monarch Prester John. They tried to explain that nowhere in Zara Yaqob's list of regnal names did that title occur. However, the delegates' admonitions did little to stop Europeans from referring to the monarch as their mythical Christian king, Prester John. He also sent a diplomatic mission to Europe (1450), asking for skilled labour. The mission was led by a Sicilian, Pietro Rombulo, who had previously been successful in a mission to India. Rombulo first visited Pope Nicholas V, but his ultimate goal was the court of Alfonso V of Aragon, who responded favorably. Two letters for Ethiopians in the holy land (from Amda Seyon and Zara Yaqob) survive in the Vatican library, referring to "the kings Ethiopia."