Where did the crusaders attack first on the first crusade?

Answer 1

Months before the planned departure of the crusade proper, a number of unexpected armies of peasants and lowly knights organised and set off for Jerusalem on their own. Known as the People's Crusade, this force attacked the Hungarian city of Semlin and burnt Belgrade, before being escorted across the Bosporus by Byzantine guides. The Byzantine emperor had warned them not to engage the Turks and to wait for the main body of crusaders who were still on the way. However, elements of the army attacked various cities until defeated by the Turks. Only a few thousand were rescued by the Byzantines, the remainder killed, or converted to Islam and sold as slaves.

The main force of the First Crusade arrived later and attacked southwards through the Levant, until it took Jerusalem in 1099 and massacred the population.