The ecclesiastical record of the ninth century mentioned Krujë as a bishop's see. The byzantine held the city up to c.1190, when the first Albanian feudal state was declared at Krujë under the archon Progon (1190-8). Arbania survived throughout the rule of Progon's son Gjin (1198-1206) and Dhimitrit (1206-16), but in 1216 it fell under the sway of Epiros, in 1230 under Bulgarians, and in 1240 again under Epiros. Foreign invaders continue to fight over the dying body of a torn and bleeding Albania until an Ottoman garrison was permanently stationed at Krujë in 1415. 
 
The youngest of Gjon Kastrioti's four sons, Gjergj, was sent with his three brothers as a hostage to the Sultan at Constantinople in 1415. He impressed his tutors at the military school he attended and they gave him the title "Skender-beg" for the valour on the field of battle. Then in 1443 he suddenly left the Ottoman army 
fighting Hunyadi, the Hungarian Hero and returned to Albania. Asthe Turks retreated near Nish on 3 November 1443, Gjergj withdrew his nephew Hamza and 300 Albanian horsemen and headed for Dibër and then Krujë. 

The citadel of Krujë became the scene of one of Europe's most titanic struggles. In May 1450 the Ottoman Sultan Murad II set out from Constantinople with a hundred thousand men to crush once and for all the Albanian army which had been united since 1444 by Skenderbeg's personal recruiting campaign. He aimed to storm the 
citadel of Krujë and to hold the Albanian countryside with Krujë as a capital. Skenderbeg's personal magnetism ensured that those 
Albanians fit to take up arms were armed and ready for combat, a total of 17,500 at the most, who were thus outnumbered by five to one. Skenderbeg divided his troops into three bands. Fifteen hundred led by Count Uran were provisioned to withstand the siege within the citadel itself. The two major forces of 8 000 each were split up, the first under Skenderbeg to harry the near of the Ottoman army once it had encamped below Kruja, and the other forming small bands of guerrilleros to ambush, raid, and snipe at the Turkish caravan on its cumbersome trail from Macedonia. Since Murad II realised that his troops would mutiny if ordered to withstand the hostile winter encamped in a trap below Kruja, after four and a half months he retreated with loses estimated at more than twenty thousand - that is exceeding the strength of the whole Albanian army. Ragusa congratulated Skenderbeg, "Magnificus et 
Potens" on his stupendous victory. 

Kruja under the direction of Skenderbeg defeated the turkish army lead by the Sultan Mehmet etc. for a quarter of a century. As the British military strategist Wolfe has said Skenderbeg surpassed 
"all the captains, both ancient and modern, in his ability to lead a small defensive army". After the death of Skenderbeg from natural causes in 1468, the citadel of Kruje defeated the Turks for more 
then ten years under the direction of Lek‘ Dugagjin till at 16 june 1478 when it fell definitively to the Sultan Mehmet. 

 

After the Ottoman took their dearly-won castle of Kruja, they rebuild the walls on the northern side, with openings for firearms, to make Kruja as impregnable against the Albanians as it had been 
impregnable against themselves. The earthquake of 1617 caused the cracking and collapse of many hill structures, including the citadel, but in 1832, on the Sultan's orders, the Albanian feudal castles were made useless for defence and a centralised 
bureaucratic government replaced - at least in intention - the former feudal semi-autonomy of the mountain regions as Kruja. Half-hearted attempts were made by the Turks to rebuild sections of the castle, after they have tightened their grip on the countryside, for they realised that sudden Balkan uprisings could overwhelm their government, and a defenceless castle is a doubtful asset to a ruling class.