638 (DCXXXVIII) ebile ngwaga wa go thoma ka Mošupologo, ngwaga wa bosenyane ngwagengsome wa 630s, ngwaga wa bomasometharo seswai ngwagengkgolo wa Ngwagakgolo 7, le ngwaga wa bomakgolo tshela masometharo seswai ngwagengkete wa Ngwagakete 1.