Complex sentence: Mehmed the Conqueror issued two such documents to the Bosnian Franciscans--the first after the conquest of Srebrenica in 1462, and the second during the military campaign in the Kingdom of Bosnia in 1463.
Split into simpler sentences: Mehmed the Conqueror issued two such documents to the Bosnian Franciscans. The first was issued after the conquest of Srebrenica in 1462, and the other during the main military campaign in the Kingdom of Bosnia in 1463.