The testament of Augustus is specified by Suetonius, (in August, c. 101, in Neron. c. 4,) who may be studied as a code of Roman antiquities. Plutarch (Opuscul. tom. ii. p. 976) is surprised.
The language of Ulpian (Fragment. tit. xx. p. 627, edit. Schulting) is almost too exclusive — solum in usû est.