Juvenal satirises insatiable ambition.

‘Acti,’ inquit, ‘nihil est, nisi Poeno milite portas frangimus et media vexillum pono Subura.’

‘Nothing is achieved’, he said, ‘unless we break the gates with a Carthaginian soldier and I plant the banner in the heart of Subura.’

Acti: driven, led. In context here, it means an action that has happened.

Inquit: he says

Nihil est: nothing is

Nisi: unless

Poeno: by means of Carthaginian

Milite: by means of soldier

Portas: gates

Frangimus: we break 

Et: and

Media: in the middle of

Vexillum: military standard, banner

Pono: I place, plant

Subura: ablative of the district of Rome