3. L.Icilius, a son of the preceding (Dionys. A. R. 11.28), is described as a man of great energy and eloquence. In his first tribunate (B. C. 456), he claimed for the tribunes the right of convoking the senate, and also carried the important law for the assignment of the Aventine (de Aventino publicando) to the plebs, notwithstanding the furious opposition of the senate and the patricians. The Aventine had up to this time been part of the domain land, enjoyed by the patricians, to whom the plebeians paid rent for the houses which they occupied. By the Icilian law the patricians were indemnified for the value of their buildings; but it was, as Niebuhr remarks, of great importance for the independence of the plebeians that the patricians should not be their landlords, and thus able to control their votes, and likewise, when bloody feuds were so likely to break out, that the plebeians should be in exclusive possession of a quarter of their own, and one too so strong as the Aventine. (Dionys. A. R. 10.31, 32 ; Liv. 3.31; Niebuhr, Hist. of Rome, vol. ii. p. 301.) In the following year (B. C. 455), Icilius and his colleagues were again elected tribunes, and proposed an agrarian law, which the patricians prevented by open violence from being put to the vote. Three patrician houses, the Cloelii, the Postumii, and the Sempronii, were brought to trial, and their property confiscated; but the patricians restored it to the accused. The discussion upon the agrarian law was then renewed, but was again interrupted by an invasion of the Aequi. (Liv. 3.31; Dionys. A. R. 10.33-43.)

Six years afterwards (B. C. 499) Icilius was one of the chief leaders in the outbreak against the decemvirs. Virginia had been betrothed to him, and he boldly defended her cause before App. Claudius; and when at length she fell by her father's hand, to save her from the lust of the decemvir, Icilius bearded the tyrant, and over her dead body roused the people to throw off the yoke of their oppressors. While Virginius induced the army on the Algidus to disown the decemvirs, and to march to the Aventine, Icilius hurried to the army which was carrying on the war against the Sabines, and prevailed upon them likewise to desert the government. Both armies subsequently united and encamped upon the Sacred Mount : the patricians were obliged to give way, the decemvirs resigned, and the tribuneship and right of appeal were restored to the plebs. The troops thereupon returned to the Aventine; and in the election of tribunes which followed, Icilius obtained the office for the third time. On his proposition, a plebiscitum was passed, securing indemnity to all who had taken part in the insurrection. He likewise took an active part in the subsequent proceedings against App. Claudius, and he in particular came forward as the accuser of the M. Claudius, the client of the decemvir, who had claimed Virginia as his slave. Icilius is mentioned once more at the close of the year as proposing to the tribes that the consuls, L. Valerius and M. Horatius, should enjoy a triumph for their victory over the Sabines, an honour which had been refused them by the senate, on account of their popularity with the plebs. The proposition was carried; and this is mentioned as the first instance in which a triumph was celebrated without the authority of the senate. (Liv. 3.44_54, 63; Dionys. A. R. 11.28-46.)

Livy (3.46) speaks of a brother of Icilius, who hastened with the son of Numitorius to the Roman army, to inform Virginius of the foul plot formed against his daughter. (Comp. Dionys. A. R. 11.37, who speaks of this Icilius under the title of νεανίσκος, by which he perhaps means to distinguish him from his brother.)

5-7. ICILII. Three of this family were elected tribunes of the plebs, in B. C. 409 (Liv. 4.54), one of whom was probably the L. Icilius, who was tribune of the plebs three years before, B. C. 412. (Liv. 4.52.) The three Icilii in their tribunate urged the plebs to elect quaestors from their own body; and this was the first time the plebeians obtained this dignity, three out of the four quaestors being chosen from them. The Icilii also made great efforts to secure the consular tribunate next year for the plebeians, but they were defeated and patricians elected. (Liv. 4.54-56.)

ICTI'NUS (Ἰκτῖνος), a contemporary of Pericles, was the architect of two of the most celebrated of the Greek temples, namely, the great temple of Athene, in the acropolis of Athens, called the Parthenon, and the temple of Apollo Epicurius, near Phigalia in Arcadia. The former was built under the administration of Pericles, and was completed in B. C. 438: Callicrates was associated with Ictinus in the work. The latter is thought to have been completed before B. C. 431, on the ground that it is not likely that Ictinus built it after the breaking out of the Peloponnesian war, an argument by no means conclusive. Ictinus was also the architect of the shrine (μυστικὸς σηκός) at Eleusis, in which the mysteries were celebrated : it was a very large building, without external porticoes, and so contrived as to accommodate a vast number of persons. All these buildings were of the Doric order. Ictinus, in conjunction with Carpion, wrote a description of the Parthenon. (Paus. 8.41.5 ; Strab. ix. pp. 395, 396; Plut. Per. 13; Vitruv. vii. Prooem. §§ 12, 16.)