linguistic:translation, structural:expansion
Crusades

Kilij Arslan, although victorious against the People's Crusade of 1096, was defeated by soldiers of the First Crusade and driven back into south-central Anatolia, where he set up his state with its capital in Konya. He defeated three Crusade contingents in the Crusade of 1101. In 1107, he ventured east and captured Mosul but died the same year fighting Malik Shah's son, Mehmed Tapar. He was the first Muslim commander against the crusades.

Meanwhile, another Rum Seljuk, Malik Shah (not to be confused with the Seljuk sultan of the same name), captured Konya. In 1116 Kilij Arslan's son, Mesud I, took the city with the help of the Danishmends. Upon Mesud's death in 1156, the sultanate controlled nearly all of central Anatolia.

The Second Crusade was announced by Pope Eugene III, and was the first of the crusades to be led by European kings, namely Louis VII of France and Conrad III of Germany, with help from a number of other European nobles. The armies of the two kings marched separately across Europe. After crossing Byzantine territory into Anatolia, both armies were separately defeated by the Seljuk Turks. The main Western Christian source, Odo of Deuil, and Syriac Christian sources claim that the Byzantine Emperor Manuel I Komnenos secretly hindered the crusaders' progress, particularly in Anatolia, where he is alleged to have deliberately ordered Turks to attack them. However, this alleged sabotage of the Crusade by the Byzantines was likely fabricated by Odo, who saw the Empire as an obstacle, and moreover Emperor Manuel had no political reason to do so. Louis and Conrad and the remnants of their armies reached Jerusalem and participated in 1148 in an ill-advised attack on Damascus, which ended in their retreat. In the end, the crusade in the east was a failure for the crusaders and a victory for the Muslims. It would ultimately have a key influence on the fall of Jerusalem and give rise to the Third Crusade at the end of the 12th century.

Mesud's son, Kilij Arslan II, is the first known Seljuk ruler who is known to have used the title of sultan and captured the remaining territories around Sivas and Malatya from the last of the Danishmends. At the Battle of Myriokephalon in 1176, Kilij Arslan II also defeated a Byzantine army led by Manuel I Komnenos. Despite a temporary occupation of Konya in 1190 by the Holy Roman Empire 's forces of the Third Crusade, the sultanate was quick to recover and consolidate its power. During the last years of Kilij Arslan II's reign, the sultanate experienced a civil war with Kaykhusraw I fighting to retain control and losing to his brother Suleiman II in 1196.

Following Kilij Arslan II's death, the sultanate was divided amongst his sons. Elbistan was given to Tughril ibn Kılıç Arslan II, but when Erzurum was taken from the Saltukids at the start of the thirteenth century, he was installed there. Tughril governed Erzurum from 1192 to 1221. During 1211–1212, he broke free from the Seljuk state. In 1230, Jahan Shah bin Tughril who was allied to the Khwarazmshah Jalal al-Din, lost the Battle of Yassıçemen, allowing for Erzurum to be annexed by the Seljuk sultanate.

Suleiman II rallied his vassal emirs and marched against Georgia, with an army of 150,000–400,000 and encamped in the Basiani valley. Tamar of Georgia quickly marshaled an army throughout her possessions and put it under command of her consort, David Soslan. Georgian troops under David Soslan made a sudden advance into Basiani and assailed the enemy's camp in 1203 or 1204. In a pitched battle, the Seljukid forces managed to roll back several attacks of the Georgians but were eventually overwhelmed and defeated. Loss of the sultan's banner to the Georgians resulted in a panic within the Seljuk ranks. Süleymanshah himself was wounded and withdrew to Erzurum. Both the Rum Seljuk and Georgian armies suffered heavy casualties, but coordinated flanking attacks won the battle for the Georgians.

Suleiman II died in 1204 and was succeeded by his son Kilij Arslan III, whose reign was unpopular. Kaykhusraw I seized Konya in 1205 reestablishing his reign. Under his rule and those of his two successors, Kaykaus I and Kayqubad I, Seljuk power in Anatolia reached its apogee. Kaykhusraw's most important achievement was the capture of the harbour of Attalia (Antalya) on the Mediterranean coast in 1207. His son Kaykaus captured Sinop and made the Empire of Trebizond his vassal in 1214. He also subjugated Cilician Armenia but in 1218 was forced to surrender the city of Aleppo, acquired from al-Kamil. Kayqubad continued to acquire lands along the Mediterranean coast from 1221 to 1225.

In the 1220s, he sent an expeditionary force across the Black Sea to Crimea. In the east he defeated the Mengujekids and began to put pressure on the Artuqids.