on 16 march 1960 he was appointed as the first bishop of wa after pope john xxiii created the new diocese. he received his episcopal consecration two months later from john xxiii himself with bishops napoléon-alexandre labrie and venerable fulton sheen serving as the co-consecrators in saint peter's basilica. poreku made his formal installation in his new see on the following 10 june and then requested permission from competent ecclesial authorities in rome to translate the mass into dagaare and have it sung in local melodies with local musical instruments; permission was given and he composed the first dagaare mass. this proved to be a significant milestone in the "africanization" of the ghanaian church.