The Italian peninsula was divided into numerous kingdoms and states during the Middle Ages, and it was not until the nineteenth-century that this land was unified into the country we call Italy.
Here are four videos to show the development of various states within Italy during the medieval period, starting with an overview video from Historical Mapping:
Potato’s Video mapping offers this video that looks at southern Italy and Sicily starting with the arrival of the Normans in 1030:
EmperorTigerstar created this video to show the Italian Wars between 1494 and 1559:
This same Youtuber has also created a video to show the Papal States from the year 774 to present:
See also: How the borders of Venice changed in the Middle Ages