Conrad, having taken ship from Constantinople, had eventually reached Acre in April 1148.

After Conrad’s arrival, a brilliant muster of French and German notables assembles with Queen Melisende, her nineteen-year-old son and co-ruler Baldwin III, and the barons of Jerusalem to discuss how best to proceed.

Despite the absence of the northern princes and the losses already suffered by the crusaders, it is possible to field an army of nearly fifty thousand men, the largest Crusade army so far assembled.

There are a number of choices for the target of the crusade.

In northern Syria, Edessa is firmly in the control of Nur ad-Din; its count, Joscelin II, is in captivity and there is no hope of retrieving him or the city, so the matter, so important to the original call for the crusade, is apparently not even discussed.

In Antioch, Raymond of Poitiers had tried to convince Louis to attack Aleppo, Nur ad-Din's capital and the greatest threat to that city, but Raymond and Louis have quarreled (partly over rumors of an incestual relationship between Eleanor and the prince) and Raymond is not present at the Council.

The County of Tripoli is also unrepresented, although an attack on Aleppo would benefit Tripoli as well; however, the rule of Raymond II of Tripoli is challenged by Alfonso Jordan, Count of Toulouse, his cousin, and when Alfonso is poisoned on the way to the Council, Raymond is implicated in his murder.

Conrad and Louis are, in any case, unconcerned with matters in northern Syria; for them, pilgrimage to Jerusalem is an inherent part of the crusading vow, and defense of Jerusalem is of utmost importance.

In the south, the most immediate threats to Jerusalem come from Fatimid-held Ascalon and the Burid Emirate of Damascus.

The crusade has coincidentally arrived during a political crisis in Jerusalem: King Baldwin III has ruled jointly with his mother Melisende since the death of King Fulk of Jerusalem in 1143, when Baldwin was only thirteen years old; but Baldwin is now eighteen and wishes to assert his authority.

The option of Ascalon does not suit Baldwin, since his brother Amalric, who supports their mother, is already Count of Jaffa and Ascalon would have been added to his territory.

Ascalon has also been contained by a number of castles built during the reign of Fulk and is not an immediate threat.

The capture of Damascus, on the other hand, would benefit Baldwin; despite being a sometime-ally of Jerusalem, Nur ad-Din also desires it, and capturing it would help limit the emir's power.

It would please Conrad and Louis, who are interested in capturing a city that, unlike Ascalon, is important to the history of Christianity.

After considerable debate reflecting the conflicting purposes of crusaders and Jerusalem barons, it is decided to attack Damascus.

The ruler of Damascus, Mu'in ad-Din Unur, has started making feverish preparations for war in response to the arrival of the Crusaders, strengthening the fortifications of Damascus, ordering troops to his city and having the water sources along the road to Damascus destroyed or diverted.

Also fearful of the expanding power of Nur ad-Din and the one Muslim ruler most disposed to cooperate with the Franks, is now forced to seek the aid of his former enemy, who is quick to move toward Damascus.

The forces from the Zengid states will not arrive in time to see combat outside of Damascus.

It is almost certain that the Zengid rulers delayed sending troops to Damascus out of the hope that their rival Unur might lose his city to the crusaders.

The crusaders, having reached a decision on June 24 at the Council of Acre to attack Damascus, had decided to attack the city from the west, where orchards will provide them with a constant food supply.

Having arrived outside the walls of the city, they immediately put it to siege, using wood from the orchards.

On July 27, the crusaders decide to move to the plain on the eastern side of the city, which is less heavily fortified but has much less food and water.

The crusaders' campaign is not only ill advised and mistakenly conceived but badly executed.

Nur ad-Din, together with Saif ad-Din, arrives with Muslim reinforcements and cuts off the crusader's route to their previous position.

Unur, however refuses them entrance, using the presence of Zangi's sons to convince the Franks to release the siege.

The local crusader lords refuse to carry on with the siege, and the three kings have no choice but to abandon the city.

On July 28, after a five-day siege, with Nur ad-Din's forces nearing the city, it becomes evident that the crusader army is dangerously exposed, and a retreat to Jerusalem is ordered, though for their entire retreat they will be followed by Turkish archers who constantly harass them.

This humiliating failure is attributable largely to the conflicting interests of the participants.

Each of the Christian forces feels betrayed by the other and mutual distrust will be fostered for a generation due to the defeat.

The Muslims, on the other hand, receive enormous encouragement by their triumph over another major Western expedition.