Prologue and Causes
The first king of Jerusalem was elected, but refused the title, instead calling himself "the protector of the holy sepulcre". He however died after less than a year of ruling, and his follower, Baldwin I had himself crowned king of Jerusalem the very same day.
However, Baldwin I died without an heir, and his cousin instead had to take the throne, until he died mysteriously in bed and his half-brother Louis the Lustful took his place, crowning himself Louis I of Jerusalem in 1136, ensuring that his family, the Rogemonds, would rule the kingdom for almost two hundred years.
Louis I was very ample to put up many fortresses and strook a deal with the then fledgling knightly order known as the Knights Hospitallers, who renamed themselves the Knights of Jerusalem. They would be granted several rights over other orders, and the county of Tripoli, which had been left without a ruler since the current count had died recently, would be given to the order. In exchange, they would supply Jerusalem with an amry of well-trained knights for protection against the turks. This later proved to be a great decision, as the military power provided by the knights would ensure Jerusalem's victory in the second and third crusades.
During this period, many Europeans moved to Jerusalem, most were French, but Italians, Germans, Greek and even a few English also arrived. The Knights of Jerusalem also held recruting campaigns in Europe, amassing a rather large army for themselves and Jerusalem.
In 1145 the count of Edessa called for help, for the turks had attacked his city and besieged it. Jerusalem sent help and called for the pope, who in turn called the second crusade.
The Crusades in the East
The future Barbarossa
The crusades this time attracted royalty from all over Europe, most importantly the future Barbarossa. The kings and queens from all over Europe sent forces to Jerusalem to help, but only two decided to come in person: Louis of France and Conrad of Germany.
While the mainland Europeans were on their way to the Holyland, the forces of Jerusalem set out to help Edessa, and arrived there in late 1145. The city had almost fallen by then, and the crusader army had to attack, which proved both a good and a bad choice, for the army of Jerusalem lost the battle, but the Seljuks were reduced in number, so the following attack from the Knights was a great success. Edessa was saved and a large Seljuk army destroyed, while the Knights had proven their worth in battle.
No time was spared, as the Knights set out to follow the fleeing army and cut down every last turk.
Meanwhile, a second turkish army had conquered the city of Damascus, and the French and German armies set out to take it back, after holding a council in Acre. The siege of Damascus was barely a success, as the muslims were without supplies and outnumbered, but most of the German and French crusaders were killed in the siege.
Now, all the crusading armies, including the knights, met in Jerusalem again. The Seljuks were no real threat anymore, as their armies were crushed, their leader had been killed in Edessa, and parts of the knights were raiding their cities to make sure no one would dare attack.
The council of Jerusalem decided that now was the time to strike into Syria and the Sinai, and conquer it for christianity. THe army was divided into two: one larger army led by Conrad of Germany and the headmaster of the Knights, a second army led by Louis of France and Louis of Jerusalem.
The two Louis headed east into Syria and Jordan, occupying cities and harrassing muslims, meeting no real resistance, while Conrad and the Knights shipped their army at great costs into Egypt over the Red Sea and launched a surprise attack on Cairo from the south. The Fatimids were not ready, and the hastily amassed army could not hold the city. It fell after a siege that lasted for 6 months. The Knights occupied the city, while Conrad led his army to Alexandria.
After the great successes, the French and Levantine armies in the east also departed for Egypt, and the collective force of the army was too much for the unprepared Fatimids, who fled west, leaving their lands without leadership and ripe for conquest. After a year of fighting, Egypt was now in Christian hands.
Conrad and Louis of France went home to Europe now, while Jerusalem continued to wage war gainst the muslims east of Jerusalem. After pacifying the region and occupying all the cities, the crusades in the east were decalred successful by the pope at the council of Alexandria, when the king of Egypt, an Italian duke from Milan, was elected as Jakob I of Egypt.
The Crusades in the West
Alfonso of Portugal
Crusaders from England, the Netherlands and Scotland left for the Holyland in 1146. Before thye arrived, though, they were intercepted along the way, as the king of Portugal, Alfonso, convinced them to instead help him fight the Muslims in western Iberia.
The crusades led by Alfonso put siege to the city of Lisbon 1147, and when the city was later captured, continued pursuing the fleeing muslims. It was then that Alfonso's army was ambushed and Alfonso killed by muslims, before help could arrive. The christian revenge was hard and strong, as they attacked the muslims, driving them further south, until finally settling in 1149, when no muslims west of Andalusia proper remained.
Now, the kingdom of Portugal should have gone to Alfonso's son, but the king of León, managed to convinced the pope that he was the rightful ruler of Portugal, and the pope declared that Portugal was now under the domains of León, which led to a violent reaction among the Castillians, who didn't like the Portuguese much. The Portuguese, however, were content with Leónese rule. later this would erupt into a revolt in Castille, leading the its independence and the loss of Leónese authority in Castille.
The south and east was still under muslim rule, but having secured Portugal was a great success, though not one of the original goals of the second crusade, which would later be remembered as the crusade that accomplished more than anyone could have hoped.
PS: Yeah, this is on the border to complete fantasy, but I felt I wanted to take some liberty in this. Also, I felt the´touch of having León as the dominant kingdom in Spain instead of Castille was too good not to take. =)