Zar'a Ya`qob or Zera Yacob (Ge'ez ዘርአ:ያዕቆብ zar'ā yāʿiqōb "Seed of Jacob," modern zer'a yā'iqōb) (1399–1468) was (19 or 20 June 1434–1468) of Ethiopia (throne name Kwestantinos I Ge'ez ቈስታንቲኖስ qʷastāntīnōs or Constantine I), and a member of the Solomonic dynasty. Born at Tilq in the province of Fatagar (now part of the Oromia Region, near the Awash River), Zara Yaqob was the youngest son of Dawit I and his youngest queen, Igzi Kebra.

The British expert on Ethiopia, Edward Ullendorff, stated that Zara Yaqob "was unquestionably the greatest ruler Ethiopia had seen since Ezana, during the heyday of Aksumite power, and none of his successors on the throne – excepted only the emperors Menelik II and Haile Selassie – can be compared to him."

Paul B. Henze repeats the tradition that the jealousy of his older brother Tewodros I forced the courtiers to take Zara Yaqob to Tigray where he was brought up in secret, and educated in Axum and at the monastery of Dabra Abbay. While admitting that this tradition "is invaluable as providing a religious background for Zar'a-Ya'iqob's career", Taddesse Tamrat dismisses this story as "very improbable in its details." The professor notes that Zara Yaqob wrote in his Mashafa Berhan that "he was brought down from the royal prison of Mount Gishan only on the eve of his accession to the throne."

Reign

Upon the death of Emperor Dawit, his older brother Tewodros ordered Zara Yaqob confined on Amba Geshen (around 1414). Despite this, Zara Yaqob's supporters kept him a perennial candidate for Emperor, helped by the rapid succession of his older brothers to the throne over the next 20 years, and left him as the oldest qualified candidate. David Buxton points out the effect that his forced seclusion had on his personality, "deprived of all contact with ordinary people or ordinary life." Thrust into a position of leadership "with no experience of the affairs of state, he [Zara Yaqob] was faced by a kingdom seething with plots and rebellions, a Church riven with heresies, and outside enemies constantly threatening invasion." Buxton continues,

Although he became Emperor in 1434, Zara Yaqob was not crowned until 1436 at Axum, where he resided for three years. It was not unusual for Ethiopian rulers to postpone their coronation until later in their reigns.

After he became Emperor, Zara Yaqob married princess Eleni, who had converted from Islam before their marriage. Eleni was the daughter of the king of Hadiya, one of the Sidamo kingdoms south of the Abay River. Although she failed to bear him any children, Eleni grew into a powerful political person. When a conspiracy involving one of his Bitwodeds came to light, Zara Yaqob reacted by appointing his two daughters, Medhan Zamada and Berhan Zamada, to these two offices. According to the Chronicle of his reign, the Emperor also appointed his daughters and nieces as governors over eight of his provinces. These appointments were not successful.

He defeated Badlay ad-Din, the Sultan of Adal at the Battle of Gomit in 1445, which consolidated his hold over the Sidamo kingdoms in the south, as well as the weak Muslim kingdoms beyond the Awash River. Similar campaigns in the north against the Agaw and the Falasha were not as successful.

After witnessing a bright light in the sky (which most historians have identified as Halley's Comet, visible in Ethiopia in 1456), Zara Yaqob founded Debre Berhan and made it his capital for the remainder of his reign.

In his later years, Zara Yaqob became more despotic. When Takla Hawariat, abbot of Dabra Libanos, criticized Yaqob's beatings and murder of men, the emperor had the abbot himself beaten and imprisoned, where he died after few months. Zara Yaqob was convinced of a plot against him in 1453, which led to more brutal actions. He increasingly became convinced that his wives and children were plotting against him, and had several of them beaten. Seyon Morgasa, the mother of the future emperor Baeda Maryam, died from this mistreatment in 1462, which led to a complete break between son and father. Eventually relations between the two were repaired, and Zara Yaqob publicly designated Baeda Maryam as his successor.

The Ethiopian church

At the time Zara Yaqob assumed the throne, the Ethiopian church had been divided over the issue of Biblical Sabbath for roughly a century. One group, loyal to the Egyptian bishops, believed that Sabbath should be observed on only one day; another group, the followers of Ewostatewos, believed with their founder that both Saturday (seventh-day Sabbath) and Sunday (first-day Sabbath) should be observed.

He was successful in persuading two recently arrived Egyptian bishops, Mikael and Gabriel, to accept a compromise aimed to restore 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 Egyptian bishops only agreed to the compromise only at the Council of Debre Mitmaq in Tegulet (1450).

Emperor 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 Dabra Mitmaq by Sultan Jaqmaq, 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 the Emperor 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 defense 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 a diplomatic mission to Europe (1450), led by a Sicilian Pietro Rombulo who had previously been successful in a mission to India, specifically asking for skilled labor. Rombulo first visited Pope Nicholas V, but his ultimate goal was the court of Alfonso V of Aragon, who responded favorably. The Catholic Ecumenical Council of Florence (1438-1445) declared that Zara Yaqob was the legendary rumored king Prester John.