He graduated from the law school Federico II in Naples, and, under the guidance of Enrico De Nicola, embarked on the study of law and economics and became a distinguished scholar of Roman law. Emeritus Professor of law at the law school Federico II in Naples, he published several tomes, among which, the History of the Roman Constitution and the Economic History of Ancient Rome; his publications were translated in English, Spanish, German, French and Chinese. He first joined the Action Party in 1943, and then joined the reconstituted Socialist party in 1945. At the first elections of the new Italian Republic in 1948, he was elected to Parliament with the Popular Front alliance of communists and socialists. He soon won the confidence of party leaderPietro Nenni, to whom he became vice secretary. When, in 1963, Nenni became Vice President of the Council of Ministers, or Deputy Prime Minister in the first centre-left government of Aldo Moro, De Martino took over as party secretary. De Martino was, in two times, the PSI's candidate to the presidential elections, in 1971 and 1978. This time, however, the more popular socialist, the former Speaker of the Chamber of Deputies, Sandro Pertini was elected. De Martino candidacy was tarnished when the family paid a 1bn lire ransom for his release his son Guido who was kidnapped by the Camorra. The kidnappers were eventually captured, but those behind them were never discovered. In 1976, he was ousted as party secretary by Bettino Craxi when the PSI lost in the elections falling below 10% for the second time. De Martino became the scapegoat, and Craxi became Italy's first socialist Prime Minister in 1983. Nonetheless, he continued to be elected to the Parliament, and, in 1992, was appointed senator for life at which point he joined the post-communist Democrats of the Left, whom he considered "the true heirs to socialist values". He was dismayed by the demise of the historical socialist party after the corruption under Craxi. He resumed his academic career at the law school Federico II, where his secular funeral was celebrated in the presence of the President of Italy, Carlo Azeglio Ciampi. He is survived by his children, Armando, Guido, Antonino, Elisa and Laura.
