At the beginning of his year of office as tribune (Dec. 67), he succeeded in getting a law passed (de libertinorum suffragiis), which gave freedmen the privilege of voting together with those who had manumitted them (i.e. in the same tribe as their patronus).
From 73 to 68 BC, Lucius Licinius Lucullus had achieved considerable success in the East, defeating both Mithridates VI of Pontus and his ally Tigranes the Great.
However, Lucullus' troops mutinied under the leadership of Publius Clodius Pulcher in 67 BC, allowing Mithridates and Tigranes to invade Pontus and Cappadocia once more.
It transferred their commands and the entire conduct of the eastern war to Pompey, who was already in the East completing his campaign against the pirates (as granted by the lex Gabinia of 67 BC).
[6] Crucially, however, it was supported by several eminent ex-consuls (unlike the lex Gabinia, which had been almost universally opposed by the Senate), as a result of which it passed unanimously in the comitia tributa.