In the 1800s and 1900s, small mediterranean kingdoms and principalities became united under a concept called
the renaissance.
nationalism.
complementarily.
city-states.

the answer is NATIONALISM

Explanation:

Option: Nationalism.

Explanation:

The urge to the nationalism began to grow in Europe after the Napoleon war. In the 1800s, Italian were prepared to build a new Italy by unifying the states together. Earlier Italians identified themselves with their local regions such as Rome, Florence, and Venice. Guiseppe Mazzini found a political movement called Young Italy (patriots) in the 1830s to unify Italy. Italy unification was necessary because of its history and one common language.

Within the Ottoman Empire, many groups such as the Bulgarians, and Romanians revolted against the Ottomans, hoping to set up independent nations.