| The arch celebrated the Parthian victories of Septimius Severus and his sons Geta and Caracalla. |
| He found Caracalla in an altered mood, rejuvenescent and in the highest spirits. |
| In January 205, Caracalla accused Plautianus for plotting to kill him and Severus. |
| In that same year Caracalla had his brother, a youth, assassinated in his mother's arms, and may have murdered 20,000 of Geta's followers. |
| Caracalla was a cruel man, and was pursued by the guilt of his brother's murder. |
| Although his son Caracalla continued campaigning the following year, he soon settled for peace. |
