The victories of Titus Vespasian
This has been preserved thanks to it's being part of the medieval fortifications of the Frangipani Family. You can find it in the Roman Forum. It was restored in the 19th century and the top bears a Latin inscription reading "The Roman Senate and People dedicate this arch to the divine Titus Vespasianus Augustus, son of the divine Vespasian."
This allusion to the divinity of Titus indicates that the emperor was dead at the time of the arch's construction. In the central relief of the dome, you can see the emperor riding an eagle, a symbol of imperial power during its ascent to the heavens. The entire arch exists to celebrate the victories of the Roman Empire under Titus and it was customary for victorious troops to pass through the arch on their return. The silver trumpets represent victory and are surrounded by allegorical characters from the time.