Answer:
By Building a large network of roads and bridges
Step-by-step explanation:
Both empires focused on the integration of their domains via the construction of a sophisticated network of roads, with its center in their respective capitals (Rome and Cuzco). Essentially, the road system not only facilitated troop movements, but also commerce and communications. For example in the case of the Incas, a messenger system (chasquis) was implemented, consisting of runners with determined distances between posts, that facilitated the spread of messages and orders.
Public works would in both cases survive the fall of the empires, with Roman roads being used well into the XVI century, and for the Incas up until the XVII century.
Hope this helps:))