A Brief History of the Roman Legions (I): Changes in the number of legions

In 30 BC, Octavian reorganized the national army, fixing the total number of imperial legions at 28. The 28 legions are:

First Germanic legion legio i germanica

Second Augusta Legion legio ii augusta

Third Augusta Legion legio iii augusta

Third Cyrenaica Legion legio iii cyrenaica

Third Gallic Legion legio iii gallica

Fourth Macedonian Legion legio iv macedonica

Fourth Western Xuya Legion legio iv scythica

Fifth Lark Legion legio v alaudae

Fifth Macedonian Legion legio v macedonica

Sixth Ferrata Legion legio vi ferrata

Sixth Victorious Legion legio vi victrix

Seventh Claudian Legion legio vii claudia

Eighth Augusta Legion legio viii augusta

Ninth Spanish Legion legio ix hispana

Tenth Gemina Legion legio x gemina

Tenth Fretensis Legion legio x fretensis

Eleventh Claudian Legion legio xi claudia

Twelfth Raiden Legion legio xii fulminata

Thirteenth Army of The Gamina legio xiii gemina

Fourteenth Gemina Victorious Legion legio xiv gemina martia victrix

Fifteenth Apollo Legion legio xv apollinaris

Sixteenth Gallic Legion legio xvi gallica

Seventeenth Legion legio xvii

Eighteenth Legion legio xviii

Nineteenth Legion legio xix

Twentieth Valerian Victory Legion legio xx valeria victrix

Twenty-first Legion of Pursuers legio xxi rapax

Twenty-second Legion of Diotaru legio xxii deiotariana

In 9 AD, at the Battle of teutonic Woods, the seventeenth, eighteenth, and nineteenth legions were annihilated, and the total number of legions dropped to 25.

In 39 AD, Emperor Caligula conscripted two new legions, bringing the total to 27.

Called:

Fifteenth Legion of Lady Luck legio xv primigenia

The xxxiith Legion of Lady Luck legio xxii primigenia

In 66 AD, Nero conscripted a new legion, totaling 28.

First Italian Legion legio i italica

From 68 AD to 70 AD, from the late Nero to the year of the Four Emperors, Nero conscripted a legion, which was later officially recognized by Otto, Galba conscripted a legion, and Mercer recruited a legion and disbanded, a total of 30.

First Auxiliary Legion legio i adiutrix

Seventh Army of The Gamina legio vii gemina

Conscription and dissolution:

First Mercer Liberator Corps legio i macriana liberatrix

In 70 AD, one legion was annihilated, and Vespa conscripted one, reorganizing two and disbanding one, for a total of 29.

Annihilated:

Second Auxiliary Legion legio ii adiutrix

Reorganization:

The Fourth Macedonian Legion lego iv macedonica was reorganized into the Fourth Flavi Lucky Legion legio iv flavia felix

The Sixteenth Gaulish Legion legio xvi gallica was reorganized into the Sixteenth Flavi Firm Legion legio xvi flavia firma

disband:

In 82 AD, Domitian conscripted a new legion, one legion was annihilated in 86 and one in 92, for a total of 28.

First Minerva Regiment legio i minervia

In 105 AD, Trajan conscripted two legions, for a total of 30.

increase:

Second Trajan Legion legio ii traiana

The thirtieth Epía Victorious Legion legio xxx ulpia victrix

From 132 to 161 AD, between the Second Jewish Revolt and the War of the East, two legions were annihilated, the details of which are unknown, a total of 28.

Twenty-second Diotaru Army legio xxii deiotariana

In 165 A.D., Aurelius conscripted two new legions, totaling 30.

Second Italian Legion legio ii italica

Third Italian Legion legio iii italica

In 197 AD, Severus conscripted three new legions, for a total of 33.

First Parthian Legion legio i parthica

Second Parthian Legion legio ii parthica

Third Parthian Legion legio iii parthica