Isotactic Polypropylene (iPP) can form different crystalline phases. This depends on the processing conditions and, for example, can be clearly observed in injection molding samples. Using X-ray scattering, the distribution of four different phases (α, β, γ, meso) over the thickness of the sample can be measured. The mesomorphic phase forms a relatively thin layer at the skin and is often neglected. However, a key issue in studying the crystallization process of semi-crystalline polymers is the need for controlled (or known) boundary and initial conditions; injection molding does not meet these requirements. Here, the results of extended dilatometry (PVT) are used to reveal the crystallization kinetics and the resulting morphology of an isotactic polypropylene homo-polymer (Borealis HD601CF) resulting from a combination of non-isothermal cooling at elevated (isobaric) pressures and shear flow. Based on the flow strength, defined in terms of the Weissenberg number, the crystallization kinetics can be classified in three regimes; quiescent crystallization, flow enhanced point nucleation and flow-induced creation of oriented structures. Using ex-situ wide angle X-ray diffraction and small angle X-ray scattering the details of the (oriented) crystalline structures for the different regimes, including three different crystalline phases (α, β, γ) and their orientation are revealed. Some unique oriented structures of combined α- and γ-phase were found. We developed a unique model in terms of a set of rate equations for the different phases, which are partially coupled. The most important ingredients of the model are: - Flow creates nuclei and shish-kebabs - Fixed portion of flow-induced nuclei is assigned to β-phase (~0.1%), the rest of them is assigned to α/γ according to their momentary crystal growth rate - Shish form parents and daughters - Parameters for crystal growth rates for all phases are taken from literature. - There are two limiting cases for the γ-phase; d