Since the Lombard kingdom had split up into a number of duchies each with its own capital, Italy, in the early Middle Ages, tended to become a group of city states, each jealous of its neighbours and ambitious only for local interests.
— from Europe in the Middle Ages by Ierne L. (Ierne Lifford) Plunket

Each tribe seems ever jealous of its neighbour; and cruel hostilities, ending in the most tragical manner—even to the extermination of a tribe and the total destruction of its cattle, stores, and property—are often the result of their mutual animosity.
— from A Sketch of Assam: With some account of the Hill Tribes by Butler, John, Major