Since none of W.A Mozart's own cadenzas for his Violin Concerto no. 4 in D major have been preserved, and there is only one existing standard cadenza by Joseph Joachim, I have chosen to write my own cadenza, but in the end I decided to write three cadenzas. As a background to my thesis I analyzed and studied the different motives in the first movement, as well as four cadenzas from different eras. I made a comparison of these four cadenzas, looking at how the composers have used the different themes and motives from the concerto. I have also explained the meaning and purpose of the term cadenza.