Season 3's explosive war between the two reignited once again in the Season 4 premiere of The Kardashians.
Much of the third season revolved around Kim accepting an offer to serve as the creative director for a Dolce & Gabbana show in Milan, which upset Kourtney because D&G designed her wedding.
The old wounds re-opened when the sisters were seeing what each other was saying about them while watching the edits, which culminated in a nasty phone call where Kourtney called Kim a 'witch' and Kim dragged her best friends and even her children into the spat.