Illusk is an ancient city that has been destroyed and rebuilt many times. The city of Luskan was built atop its ruins.
After almost 900 years, the city and it's people were crushed under a giant-led orc horde, even help from Jeriah Chronus and his Netherese arcanists couldn't save Illusk. However, in -425 DR the Netherese returned to refound the city as a magocracy ruled by a Grand Cabal of mages led by Fynran the Flamelord. In -354 DR another Netherese arcanist named Melathlar arrives in Illusk, fleeing the phaerimms. Fearing that he would be followed, Melathlar sarificed himself to magically erect the Host Tower of the Arcane as well as huge stone walls and spellwards. Over the next several years more and more Netherese refugees migrate to Illusk as their homes in Low Netheril are wasted by the phaerimm lifedrain magic.
In -111 DR several orc hordes sweep down from the Spine of the world at once and wipe out both Illusk and Gauntlgrym as well as most of Delzoun. Most of the citizens of Illusk manage to flee and the local elf population unites to defeat the orcs. The resiliant netherese descendants then begin rebuilding their homes three years later, restoring Illusk to it's former state.
The Grand Cabal became imperialistic in -15 DR and expand their borders south and east, as a result, they quickly met with elven resistance which then became organized so that in -10 DR an elven army led by Lord Halueth Never attacks and defeats Illusk, though they fail to extinguish all illuskan resistance. After long peace talks, the illuskans and the elves agree on making the Mirar the border between their realms.
A century afterwards, in -95 DR, Ruathens returned to Illusk, this time as invaders. They slew the Grand Cabal but the rest of the wizards retreated into the Host Tower. Expecting to be hailed as heros, the Ruathens were surprised when the illuskan people burned their ships and drove them out of the city. Over the next year, Stephan Blackspear drove the remaining wizards out of the city and established himself as Highlord of the city.
56 years after this change in government, Illusk, possibly weakened by the effort to rebuild Gauntlgrym is captured by yet another orc horde and renamed Argrock. This change doesn't last and after the orcs are driven out the city is recolonized by settlers from Yarlith, Uthtower and the Mlembryn lands. Taman Steeldrake rises to lead these colonists as the first Grand Prince of Illusk.
in 306 DR Illusk was attacked again by an orc horde, though this time it was defeated by an army of mercenaries. Though it wasn't so lucky 305 years later when the Everhorde leaves the city in ruins with only the Host Tower surviving the assault. It takes 200 years to rebuild Illusk but by the time the construction is finished, the city is already prospering thanks to flourishing trade with Mirabar. This profit is used to obtain resources in order to build strong defensive walls. The city gains strong ties with Stornanter thanks to their mutual trading ties to Mirabar and then even more so when a Duke of Stornanter becomes the ruler of Illusk. After centuries of trade and successfully repelling attacks from uthgardt, a Grand Prince named Galnorn tried and failed to conquer Mirabar in 1023 DR. 21 years later, a neverwinteran wizard revealed Galnorn to be a doppleganger and slew it.
In 1235 DR, another band of orcs, calling themselves the Bloody Tusk tribe attacked and beseiged Illusk. They continue the siege for 9 long years, ruining the city, until the last human resistance was defeated. The orcs used the ruins as a fortified bandit camp for 57 years until a waterdhavian mercenary army clears the ruins and with help from Neverwinter, the city is rebuilt and renamed Luskan by the next year.