3. Q.MarciusPhilippus, L. F. Q. N., son of No. 2, was praetor B. C. 188, and obtained Sicily as his province. Two years afterwards, B. C. 186, he was consul with Sp. Postunmius Albinus. These consuls were commanded by the senate to conduct the celebrated inquiry into the worship of Bacchus, which had been secretly introduced into Italy and been the occasion of much immorality and profanity. We accordingly find the name of Philippus in the senatus consultum de Bacchanalibus, which has come down to us. After Philippus had finished his share in these investigations, he set out for Liguria, where he and his colleague had to carry on war. Here, however, he was unsuccessful. In the country of the Apuani, he was surprised by the enemy in a narrow pass, and lost 4000 of his men. The recollection of his defeat was preserved by the name of the saltus Marcius, which was given to the spot from this time. In B. C. 183, Philippus was sent as ambassador into Macedonia, with orders to watch likewise the Roman interests in Southern Greece; and although he compelled Philippus to withdraw his garrisons from various places, yet the report which he presented to the senate was unfavourable to the Macedonian monarch. In B. C. 180. Philippus was chosen a decemvir sacrorum. Some years afterwards, B. C. 171, Philippus was again sent with several others as ambassador into Greece to counteract the designs and influence of Perseus. he and Atilius were ordered first to visit Epeirus, Aetolia, and Thessaly, next to proceed to Boeotia and Euboea, and from thence to cross over to Peloponnesus, where they were to join their other colleagues. In Thessaly Philippus received an embassy from Perseus, praying for a conference, and grounding his plea on the hospitable connection which had been established between his father and the father of the Roman ambassador. With this request Philippus complied, and the conference took place on the banks of the river Peneus. The Roman ambassador persuaded the king to send ambassadors to Rome, and for this purpose a suspension of hostilities was agreed upon; and thus Philippus completely accomplished the object he had in view, as the Romans were not yet prepared to carry on the war. Philippus next went to Boeotia, where he was also successful in carrying out the Roman views, and he then returned to Rome. In the report of the embassy which he gave to the senate, he dwelt with pride upon the way in which he had deceived Perseus; and although the senators of the old school denounced such conduct as unworthy of their ancestors, the majority of the body viewed it with so much approbation as to send Philippus again into Greece, with unlimited power to do whatever he might think most for the interest of the state.

These services did not go unrewarded, and in B. C. 169 Philippus was a second time chosen consul, and had as his colleague Cn. Servilius Caepio. The conduct of the Macedonian war fell to Philippus. This war had already lasted two campaigns, during which Perseus had maintained his ground against two consular armies. Philippus lost no time in crossing over into Greece, where he arrived early in the spring of B. C. 169, and received in Thessaly the army of the consul of the preceding year, A. Hostilius Mancinus. Here he did not remain long, but resolved to cross over the mountain ridge of Olympus and thus descend into Macedonia near Heracleium. Perseus was stationed with the main body of his forces near Dium, and had taken possession of the mountain passes which led into the plain. If Perseus had remained firm, he might have cut off the Roman army, or compelled it to retrace its steps across the mountains with great loss; but, at the approach of the consul, he lost courage, forfeited the advantages of his position, and retreated to Pydna. Philippus followed him, but was unable to accomplish any thing worthy of mention, and in the following year handed over the army to his successor L. Aemilius Paulus, who brought the war to a close. We learn from Livy that Philippus was at this time more than sixty years of age. In B. C. 164, Philippus was censor with L. Aemilius Paulus, and in his censorship he set up in the city a new sun dial. (Liv. 38.35, 39.6, 14, 20, 48, 40.2, 3, 42, 42.37-47, 43.13, 44.1_16; Plb. 24.4, 6, 10, 27.1, 28.10, &c.; Plin. Nat. 7.60; Cic. Brut. 20.