Procatalyst comprising an inorganic support, a chlorine compound carried on said support, a magnesium compound carried on said support, a titanium compound carried on said support, and a compound comprising two oxygen containing rings, wherein said two rings are linked via a bridge selected from the group consisting of carbon bridge, silicon bridge, ethane-1.2-diyl bridge, ethene-1,2-diyl bridge, alkylaminomethyl bridge and imine bridge.