Medieval Military History

General

De Re Militari:  The Society for Medieval Military History  (The Society)

        The website of a scholarly association interested in the study of medieval and early modern warfare.  The site has English, Italian, French, and Spanish versions.  Its Online Resources link (highly recommended) provides classified links to general and thematic bibliographies, book reviews, many full-text books, articles, dissertations, primary sources, course syllabi, identified movies, TV, radio programs, and provides a blog.   There are also special sections on The Byzantine Empire, Vikings & Scandinavian Warfare, Anglo-Norman Warfare, Crusades, The Mongols, and Hundred Years' War.  The Home Page's right-hand column includes its "latest additions".  This is a site that rewards exploration.  Membership, I believe, opens more doors, for those interested.

Medieval Warfare (The Hundred Years War.com) 

            Main clickable sections:  Evolution of Medieval Warfare.  -- Recruiting, Organization & Tactics. -- Pay for the Troops. -- Logistics.  -- Just War.  -- Ransom for Those Captured in Battle.  -- Siege Warfare.  -- Chivalry.  Uses a narrative format, with clickable explanatory or elaborative links (some short some more involved and informative).   

NetSERF:  The Internet Connection for Medieval Resources, Dr. Andrea R.Harbin, editor, & Beau A.C. Harbin (NetSERF)

        While the site itself is concerned with medieval history,in general, it is searchable, and offers many links directly or indirectly related to medieval military history, under its 13 main headings.  Its left-hand column is also worth exploring, particularly its Medieval Glossary, 3 Top Medieval Sites (all fine choices for exploring and rooting out medieval things military:  ORB, Internet Medieval Sourcebook, and Labyrinth), and its Medieval News section.    

C.  Medieval  (Web Sources for Military History), by Richard Jensen

        When the links work, they are good ones, and provide good overview material in a variety of forms.

Medieval Military History (Hillsdale College, Hillsdale, MI)

        A short, well-selected section of period documents transcribed & rendered in English.

The Orb: Online Reference Book for Medieval Studies (City University of New York. College of Staten Island)

        A searchable, major, general website on medieval history, including its military aspects.

Sociéte de l'Oriflamme (The Society) 

        While mostly, but not exclusively concentrated on late medieval Anglo-French military history, focused on the Norman and Angevin dynasties and empire and the Hundred Years' War, it also includes links on the Crusades (including the Albigensian Crusade). 

Artillery

Siege Engine Info, [comp. by] Jeff Mann & Josh James (University of Alaska @ Fairbanks. The Physics of the Trebuchet)

Trebuchet.com (RTL Industries)

        Also contains a link to Mangonel.com, another type of medieval siege engine.

Bibliography

Medieval Warfare Bibliography (De Re Militarii)

        Arranged by publication year, in reverse chronological order (starting with the most recent year), followed by Dissertations & Theses (1990-2005), a First Crusade Bibliography, and more.      

Castles and Fortifications

Medieval Fortification (Wikipedia)

        Organized in 4 main sections:  Fortification Types, Construction, Dismantling Fortifications, and Defensive Obstacles,  and a "see also" section.

Chronology

Medieval Military History Timelines (About.com) 

        Timelines of the Crusades, Teutonic Order, Hundred Years' War, and in a technological vein, separately, of the Crossbow and Longbow.  In the left-hand column, mixed among other things are links on Medieval History, the Medieval Church, a Medieval Atlas, Medieval biography, and a host of thematic and commercial links (caveat emptor).

Documents

Medieval Military History (Hillsdale College)

        A short, manageable introductory selection of transcribed and translated documents.

Charlemagne, Empire of

The Frankish Kingdom, [comp. by] Örjan Martinsson (tacitus.nu)

            Essentially a series of maps and accompanying explanatory text, showing the Frankish domain, from its establishment as a foederati (Allied) enclave within the Roman Empire, to the death of Charlemagne.

Germanic Invasions

The Germanic Invasions of Western Europe (University of Calgary.  First Europe Tutorial)

        Includes narrative, maps, and links to (transcribed and translated)primary sources, as well as to other phases of medieval history.

Stirrup

The Stirrup and Its Effect on Chinese Military History, by Prof. Albert Dien (Silk-Road.com)

Magyar Invasions

The Red Kaganate:  The Magyars of Hungary, by Steven Lowe  (Red Kaganate.org)

A Thousand Yeas of the Hungarian Art of War (Hungarian History.hu)

Viking Invasions

Viking Age History (Hurstwik.org)

Viking Warriors, Armor, Weapons, and Warfare (The Viking Answer Lady)

Vikings and Scandinavian History (About.com.  Medieval History.  People and Places)

Crusades

The Crusades (Internet Medieval Sourcebook)

The Crusades (Wikipedia)

The Crusades (The Orb)

Japan

Samurai, Ninja, and Medieval Japan Site (Ron Knight)

Mongol Empire

Mongols in World History (Columbia University)

Genghis Khan on the Web (Isidore-of-Seville.com)

Matching Genghis Khan (Family Tree DNA)

The Mongol Khans (Proceedings of the Friesian School, Fourth Series)

Mongol Military Tactics and Organization (Wikipedia)

Communications (Geocitites.com)

The Mongol Empire, by Carol A. Keller, graphics by Mary Emerson (San Antonio College)

Mongol Empire (Wikipedia)

Mongol Invasion of Europe (Wikipedia)