The present invention provides a method of preparing polycarbonate, said method comprising (A) oligomerising in the presence of a catalyst at least one dihydroxyaromatic compound at a temperature in a range between about 220-280° C. and a pressure in a range between 180 mbar and 20 mbar, said catalyst comprising a tetraarylphosphonium compound and optionally a co-catalyst, to provide an oligomeric polycarbonate having a number average molecular weight, Mn, in a range between about 1000 and about 6000 daltons; and (B) in a second step heating the oligomeric polycarbonate formed in step (A) at a temperature range between about 280 and about 310° C. and a pressure in a range between about 15 mbar and about 0.1 mbar, to provide a polycarbonate having a weight average molecular weight, in a range between about 15,000 and about 50,000 daltons, said product polycarbonate comprising less than 1000 parts per million Fries product.