Even for the crusader’s army, it was not possible to directly infiltrate Jerusalem. It was the motto of Crusade – To take back the holy land. But the threats Byzantine empire were also real, and for that purpose, one common target was necessary. That common target was Nicaea.
Nicaea was large and massive, A prosperous city located in the Bosporus. Nicaea was essential geographically. It was perfect to rule because it cannot be perfectly sieged. It had no land from the Westside, and it is challenging to hold the siege from Seawater. Kilij Arslan declared this City as the capital of his kingdom.