Final answer:
Venice was the Italian city-state that had begun to build a commercial trade empire in the Mediterranean Sea by 1400.
Step-by-step explanation:
In 15th century Italy, the city-state of Venice had begun to build a commercial trade empire in the Mediterranean Sea by 1400. Venice had control of part of the Silk Roads, which brought silk, spices, and other luxury goods from East Asia. Their dominance in trade routes and their strategic location allowed them to establish a vast trading network, bringing wealth and prosperity to the city.