When the Ottoman Empire started to capture more and more European territory, the Popes sent missionaries to the Balkans to spy on the Ottoman forces and their organization of the territories they captured. One of the missionaries was Martin Segon. Pope Sixtus IV instructed Martin Segon to travel across the Balkans and investigate routes which could be used to intercept the Ottomans. He sent the text he wrote to pope Sixtus IV at the beginning of 1480, before Gedik Ahmed Pasha organized the Ottoman invasion of Otranto. Segon's report overcame its main purpose because it included Segon's observations mainly about Serbia (and in less extent other regions) at the end of the 15th century, its history, ethnology, geography, castles, monasteries, Ragusan traders, people and their character, Battle of Kosovo, epic poetry etc. Felix Petančić used the manuscript written by Martin Segon and published it in 1522 under the title "De itineribus in Turciam libellus".