Yeshaq, according to the Islamic historian al-Maqrizi, hired a group of Mamluks led by al-Tabingha to train his army in gunnery and swordfighting, they also taught him the secrets of Greek fire.
[8] Further, George Wynn Brereton Huntingford suggests that it was during Yeshaq's reign that the rulers of Ethiopia ceased having permanent capitals; instead, their courts were held in their encampments as they progressed around their realm.
He sent a letter by two dignitaries to Alfonso V of Aragon, which reached the king in 1428, proposing an alliance against the Muslims and would be sealed by a dual marriage, that would require Infante Peter to bring a group of artisans to Ethiopia, where he would marry Yeshaq's daughter.
[11] The first mention of the Yem people is found (under the now pejorative exonym "Jangero") in the victory song of Yishaq I, with them stated as paying tribute in the form of horses to the king.
[12] The first mention of the ethnonym "Somali" dates to the reign of Emperor Yishaq who had one of his court officials compose a hymn celebrating a military victory over the Sultan of Ifat's and his eponymous troops.
[13] E. A. Wallis Budge states that he was assassinated, and "buried in Tadbaba Maryam", a convent in Sayint,[14] while Ethiopian historian Tadesse Tamrat believes that the primary sources mask Yeshaq's death in battle against the Muslim Adalites under the Adal Sultan Jamal ad-Din II.