How did the Second Crusade differ in aims and execution from the First?

The Second Crusade differed from the First in its aims to recapture Edessa and its execution through multiple fronts.

The First Crusade, launched in 1095, was primarily a response to the Seljuk Turks' invasion of the Byzantine Empire and their capture of Jerusalem. Its main aim was to reclaim the Holy Land, particularly Jerusalem, from Muslim control. The Crusaders, largely from Western Europe, were united in their goal and followed a single route through Anatolia to Jerusalem, which they successfully captured in 1099.

In contrast, the Second Crusade, called in 1145, was triggered by the fall of the County of Edessa, a Crusader state established during the First Crusade, to the Muslims. While the recapture of Jerusalem remained a spiritual motivation, the immediate objective was to retake Edessa. This marked a shift in the strategic focus of the Crusades from the Holy Land to the broader Levant.

The execution of the Second Crusade also differed significantly. Instead of a single unified force, the Crusaders operated on two fronts. The first, led by the French King Louis VII and the German Emperor Conrad III, aimed at Edessa. The second, led by the Kings of Portugal, Aragon and Navarre, targeted Muslim territories in the Iberian Peninsula and the Moors in Lisbon. This multi-front strategy was a departure from the First Crusade's single-front approach.

Moreover, the Second Crusade was marked by a lack of coordination and unity among the Crusaders, leading to its ultimate failure. The German forces suffered a disastrous defeat in Anatolia, while the French were unable to recapture Edessa. In the Iberian Peninsula, although the Crusaders achieved some success, it did not significantly alter the balance of power.

In summary, the Second Crusade differed from the First in its immediate aim of recapturing Edessa and its execution through multiple fronts. These differences, particularly the lack of unity and coordination, contributed to its failure, contrasting with the success of the First Crusade.