1. In Renaissance Italy especially. While most of the Italian communes were republics in the 11th, 12th and 13th centuries, by the beginning of the 14th most had become principalities, with the notable exceptions of Venice, Florence, Lucca, and a few others. (And even then, Florence and Lucca became Dukedoms by the mid-16th century).
2. They’re not that separated. The Narrow Sea is a narrow one, after all.