A method of making an olefin polymerization catalyst is disclosed. The method first combines a magnesium halide with an alcohol, then adds a hydroxylated ester and a silicon alkoxide, followed by a titanium compound and another silicon compound to result in a solid composition. This solid composition is then reacted with an aluminum compound and an alkyl halide, followed by reaction with a second titanium compound which may be the same as or different from the first. The second silicon compound is preferably a silicon halide, and the titanium compounds are preferably halides and alkoxides. The aluminum compounds preferably have chloride and alkyl ligands bonded to them.