The number of legions gradually rose to 30 and with one minor fluctuation under Marcus Aurelius it remained at that level until Septimius Severus, who raised another 3.

• 军团的数目逐步增加到30个；除了在马克·奥雷利乌斯治下曾有过小的波动以外，其数目一直维持如此；直至塞普提米乌斯·塞维鲁斯时期；他又征募了另外3个军团.