The Tactica (Greek: Τακτικά) is a military treatise written by or on behalf of Byzantine Emperor Leo VI the Wise in c. 895–908 and later edited by his son, Constantine VII. Drawing on earlier authors such as Aelian, Onasander and the Strategikon of emperor Maurice, it is one of the major works on Byzantine military tactics, written on the eve of Byzantium's "age of reconquest". The original Greek title is τῶν ἐν πολέμοις τακτικῶν σύντομος παράδοσις ("short instruction of the tactics of war"). The Tactica elaborates on a wide variety of issues, such as infantry and cavalry formations, drills, siege and naval warfare etc. It is written in a legislative form of language and comprises 20 Constitutions (Διατάξεις Diataxeis) and an Epilogue and is concluded by 12 additional chapters, the latter mainly focusing on ancient tactics.
The text of the Tactica is transmitted in several manuscript prototypes, of which the most authoritative date to within a generation of Leo himself. Leo mentions within the Tactica, that Christianity could adopt Islam's doctrine of a "holy war" for its military applications.
An edition with English translation by G. T. Dennis (ed.), The Taktika of Leo VI. Text, Translation and Commentary ([CFHB 49] Dumbarton Oaks, Washington, D.C. 2010), was translated from a 10th-century Florentine manuscript.
- Chapter I - On Tactics and On the General
- Chapter II -On who the General should be
- Chapter III - On how the Decision should be taken
- Chapter IV - On the Division of the Host and the Condition of the Officers
- Chapter V - On Arms
- Chapter VI - On the Equipment of Cavalry and Infantry
- Chapter VII - On Drilling Infantry and Cavalry
- Chapter VIII - On Military Punishments
- Chapter IX - On Marching
- Chapter X - On Baggage Trains
- Chapter XI - On Camps
- Chapter XII - On Military Preparation
- Chapter XIII - On the Day before Battle
- Chapter XIV - On the Day of Battle
- Chapter XV - On Besieging a Town
- Chapter XVI - On the Actions after the War is Concluded
- Chapter XVII - On Surprise Attacks
- Chapter XVIII - On the Studying of Various Heathen and Roman Formations
- Chapter XIX - On Naval Warfare
- Chapter XX - On Various Maxims
Additions from the Sylloge Tacticorum
- Chapter XXXII - Their (Ancient Greek) Infantry Formations
- Chapter XXXIII - Their (Ancient Greek) Cavalry Formations
- Chapter XXXIV - Their (Ancient Greek) Mixed Formations
- Chapter XXXV - How the Romans Name the Officers of the Army and their Units
- Chapter XXXVIII - Roman Infantry Arms
- Chapter XXXIX - Roman Cavalry Arms
- Chapter XLI - Names of Troop Maneuvers
- Chapter XLII - Phalanx Formations
- Chapter XLIII - On Depth, that is the Depth of Infantry and Cavalry Formations, their Length and the Space Occupied by an Infantryman within the Formation, the Cavalryman and on the Interval between them within the Formations and on the Flight of an Arrow.
- Chapter LIII - What the General Should Do When Besieged
- Chapter LIV - What Should the General Do When Besieging the Enemy
- Chapter LV - How Should the General Speedily Build a Fort close to Enemy Border Without a Pitched Battle
- Religious service for Byzantine soldiers and the possibility of Martyrdom, c.400 - c.1000, Paul Stephenson: "Just Wars, Holy Wars, and Jihads: Christian, Jewish, and Muslim Encounters and Exchanges", ed. Sohail H. Hashmi (Oxford University Press, 2012), 35.
- Edward N. Luttwak, The Grand Strategy of the Byzantine Empire (Harvard University Press, 2009), 305.
- Shaun Tougher, The Reign of Leo VI (886-912): Politics and People (Brill, 1997), 169.
- Bernard Lewis, The Middle East:A brief history of the last 2000 years (Scribner, 1995), 234–235.
- George Dennis, The Taktika of Leo VI (Dumbarton Oaks, 2010), xiii.