20th Mechanized Infantry Division

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20th Mechanized Infantry Division
Formed Between 2571 and 2577
Disbanded Disbanded in 2784
Nickname Longhorn Stampede[1]
Affiliation Star League
Parent Command LIII Corps



The Twentieth Mechanized Infantry Division was a part of the Star League Defense Force Regular Army. It was originally formed as the 20th Division during the creation of the SLDF in 2571, and was a part of VII Corps during the Reunification War, where it served in the Magistracy of Canopus campaign from 2577 to 2588.[2][3] Despite not using the Mechanized Infantry designation laid down within the doctrine and organization originally defined for divisions during the creation of the SLDF, the 19th most likely formed up as a mélange of combined arms units.[4] The breakdown for the SLDF element of the Canopian task force indicates that just under a half of the SLDF regiments were BattleMech regiments, one-third were infantry regiments and the remaining forces were a mix of armor and aerospace regiments.[5]

Reunification War[edit]

As a part of the Magistracy of Canopus task force, the 20th was stationed on Tellman's Mistake when military action against the Magistracy began. The 20th didn't undertake an offensive action at division strength during the Magistracy of Canopus campaign, but the Commanding Officer of VII Corps, Captain-General Marion Marik, would often assign a division or more of troops to the conquest of various worlds by drawing together brigades from across VII Corps. Brigades from the 20th operated in conjunction with independent regiments from within VII Corps as well as fighting alongside units from the Free Worlds League Military assigned to the task force as auxiliary forces.[2][3]

Brigades from the 20th captured the worlds of Cranston, Vakarel and Butzfleth in 2577, acting alongside various FWLM and independent SLDF regiments. It was on Cranston that the 58th Brigade was surprised by the highly mobile defense that became the watchword for Magistracy Armed Forces tactics during the war, when an elaborate shell game and a daring pirate-point insertion left the 58th Brigade fighting the 1st Canopian Grenadiers and the 3rd Canopian Light Horse. This battle led to the SLDF invasion plans being redrawn to compensate for a much more spirited and flexible defense than had originally been anticipated. Further changes were made when the Magistracy Navy ambushed the 59th Brigade and its supporting naval forces in the Vakarel system, turning a time-consuming but generally low-key planetary campaign into an ambush that stung the SLDF and saw numerous losses amongst the SLDF transport elements, as well as the loss of two complete battalions of troops from the 59th when their transport ships were destroyed.[2][6][7]

The 58th Brigade worked alongside forces from the 21st Royal Division in 2578 to capture Ruschegg, while in 2579 the other 20th Division forces captured the world of Bethonolog, perhaps the most civilized battle of the war, where the 20th Division forces honored a request from the local militia commander to postpone the battle until after the festive holiday season and even exchanged gifts with the local militia.[8] Whilst the 19th Division and the 21st Royal Division went through a period of refit and rearmament in 2580 and 2581 the 20th Division was busy, capturing the worlds of Aspropirgos and Gallis in the first year and the worlds of Borgan's Rift and Fanardir in the second, low-key campaigns that saw the defending MAF forces contest the invasions but retreat swiftly after stinging the 20th, preserving their strength for later battles.[2]

As the SLDF campaign picked up pace in 2582 the 20th Division saw action again on Adherlwin and Royal Foxx, but the most important battle of the year was for the key industrial world of Tetski, site of some of the Magistracy's largest BattleMech repair facilities; the 58th Brigade and two FWLM regiments followed up on a daring distraction raid by the 1st Marik Militia that drew the defending 3rd Canopian Light Horse away from the main industrial complex and nearly managed to capture the Canopian forces in the open. Instead, they ended up fighting a bloody battle against the Canopian troops who fought to the last man, refusing multiple offers to surrender.[2][9]

As a part of the general encirclement of Canopus IV, the 20th Division was responsible for capturing the worlds of Early Dawn, Krimari and Megarez in 2583 and then Brixtana in 2584 before the 58th and 60th Brigades were deployed as a part of the invasion of Canopus itself. The Canopus campaign took several weeks and the final battle around the capital city, Delphi, resembled a meat grinder until the Canopian forces surrendered; only the 59th Brigade would see combat during the next two years, capturing the world of Techne's Revenge in 2585 while the 58th and 60th rebuilt and secured the Star League occupation of Canopus.[3]

During the closing stages of the war the 59th Brigade would continue to serve as the operational brigade from the 20th Division, working with supporting forces to push the 2nd Canopian Light Horse and Buquoy's Bandits from Wildwood in 2587 before working with the 56th Brigade and the 401st Independent Regiment to capture Hardcore in one of the final battles of the war in 2588.[3]

Amaris Civil War[edit]

In 2764 the 20th Mechanized Infantry Division was a part of the LIII Corps, Seventh Army, and was assigned to District 3 of the Capellan Confederation Military Region but was moved to an undisclosed area of the Periphery to take part in the Periphery campaign following the New Vandenberg Uprising in 2765.[10] The 20th suffered heavy losses in the Hegemony Campaign, and was disbanded in 2784.[10]


Rank Name Command
Commanding Officers of the 20th Mechanized Infantry Division
Major General Tiffany Mopp 2764[1]


The Mechanized Infantry Divisions of the Star League were used offensively to exploit gaps in the enemy front created by the BattleMech Divisions. They also bore the brunt of defensive actions.

Composition History[edit]


The 19th Division (3 Brigades)[2]

  • CO: General Mancini[7]


The Division comprised two Brigades of Mechanized Infantry and a single BattleMech Brigade. Also attached was a Ground Aero Wing.[11]


It was confirmed by the author of Historical: Reunification War that in general, the Divisions listed within the Star League sourcebook be traced back directly to those Divisions listed within Historical: Reunification War.[12] Therefore, it can safely be assumed that the 26th Century 20th Division is the direct antecedent of the 28th Century 20th Mechanized Infantry Division.


  1. 1.0 1.1 Field Manual: SLDF, p. 97
  2. 2.0 2.1 2.2 2.3 2.4 2.5 Historical: Reunification War, p. 148: "Magistracy of Canopus Front (Jump-Off &ndash 2582)"
  3. 3.0 3.1 3.2 3.3 Historical: Reunification War, p. 149: "Magistracy of Canopus Front (2583 &ndash 2588)"
  4. Historical: Reunification War, p. 27: "Divisions and Brigades"
  5. Historical: Reunification War, p. 95: "SLDF Task Force Canopus"
  6. 6.0 6.1 Historical: Reunification War, pp. 97–98: "Restitution and Cranston (October-November 2577)"
  7. 7.0 7.1 Historical: Reunification War, p. 98: "Butzfleth and Vakarel (October-November 2577)"
  8. Historical: Reunification War, pp. 100–101: "Eleusis, Obrenovac and Bethonolog (October-November 2577)"
  9. 9.0 9.1 Historical: Reunification War, pp. 101–102: "Tetski (September-November 2582)"
  10. 10.0 10.1 The Star League, p. 154: "Seventh"
  11. The Star League, p. 133
  12. Ask The Writers: Star League Divisions: Reunification War to Liberation of Terra (dead link)