Nehemiah possibly was born into a highborn family in the 1030s. He is first appeared as archbishop in the founding charter of the Benedictine Abbey of Garamszentbenedek in 1075. Historian László Koszta considered Nehemiah already held the dignity during the last regnal years of the young Solomon. In 1073, peace talks were held in Esztergom between Solomon and Géza, where they concluded a truce with the possible mediation of Nehemiah. After the decisive battle of Mogyoród on 14 March 1074, the archbishop supported Géza's claim to the Hungarian throne. It is possible that the new monarch had approached Pope Gregory VII to obtain international recognition of his rule through Archbishop Nehemiah. In March 1075, Pope Gregory referred to that he has heard many good things about the king and his actions. In April, Gregory recognized Géza's legitimation. Nehemian crowned Géza with a gold and enamel diadem, sent by Byzantine Emperor Michael VII Doukas in the spring of 1075. That diadem later became the lower part of the Holy Crown of Hungary. During the Investiture Controversy, Nehemiah sent his envoy to Rome at the end of 1076. This unidentified envoy was present during the turbulent events in the next year, including the so-called Road to Canossa. Nehemiah was a strong supporter of the Gregorian Reforms. Nehemiah is next mentioned by a letter of Pope Gregory VII on 9 June 1077, when requested the archbishop to intercede with Ladislaus in the interest of a diplomatic mission to the papal court. This letter suggests that Nehemiah functioned as a liaison between the Roman Curia and the Hungarian royal court. It is possible that Ladislaus I, who controversially ascended the throne after his brother's death, was crowned king around 1078 by Nehemiah. Under the influence of Nehemiah, the new king supported the pope and Emperor Henry IV's opponents during the Investiture Controversy. In 1079, Pope Gregory again sent a letter to Ladislaus regarding the subject of the king's diplomatic mission to Rome. As he did not mention Nehemiah despite his previous participation in the compilation of the composition of the legation, it is presumable that he died by then.
