Final answer:
The outcomes of the military campaigns against Davan are not provided in the historical references available; instead, various historical contexts and general principles of warfare are discussed.
Step-by-step explanation:
The outcomes of the two military campaigns launched against Davan over four years are not specified in the historical references provided. Instead, information from various military campaigns and strategies throughout history, including tactics and consequences of prolonged warfare, are discussed. These references span several historical contexts, from general principles in warfare to specifics of famous military campaigns and battles such as Shivaji's resistance against the Mughal Empire, Napoleon's campaigns in Europe and the Middle East, Heraclius' war with the Sasanian dynasty, and World War II strategies. None of these references directly provide an outcome specific to the military campaigns against Davan.