Spurius Cassius Viscellinus or Vecellinus (d. 485 BC) was one of the most distinguished men of the early Roman Republic. He was three times consul, and celebrated two triumphs. He was the first magister equitum, and the author of the first agrarian law. The year following his last consulship, he was accused of aiming at regal power, and was put to death by the patricians.
From his filiation, Spurius Cassius S. f. S. n. Viscellinus, we know that Cassius' father and grandfather were both named Spurius. According to one tradition, his father was still living and hale at the time of his death. If this were the case, it would be difficult to place Cassius' birth much earlier than 540 or 535 BC. Cassius also left behind him three sons, whose names have not been preserved. It is believed that the Cassii Viscellini were patricians, although the later members of the gens occurring in history were all plebeian. The historian Niebuhr suggests that Cassius' sons may have been expelled by the patricians from their order, or that they or their descendants may have voluntarily passed over to the plebeians, because the patricians had shed the blood of their father.
Cassius' first consulship was in 502 BC, the eighth year of the Republic. His colleague was Opiter Verginius Tricostus. Dionysius reports that Cassius carried on war against the Sabines, whom he defeated with great loss near Cures. The Sabines sued for peace, and surrendered a large portion of their land. On his return to Rome, Cassius celebrated his first triumph, which is confirmed by the Fasti Triumphales. Livius, however, states that the two consuls carried on war against the Aurunci, and took the town of Suessa Pometia. The same events he reports under BC 495, which is in agreement with Dionysius. Thus, Dionysius probably preserves the correct account.