When researching the Revolutionary War one is constantly keeping an eye out for primary source materials. Some of those sources are the very same books read by the people we study, including the wide range of books on military science published during the seventeen hundreds. Thomas Simes was one of the most prolific military writers of the era, responsible for at least six significant textbooks some of which were used by armies on both sides of the American Revolution. His works, published in Dublin and London, had many subscribers and were printed in many editions. Some were used as textbooks in Lewis Lochée’s military academy, which produced many British staff officers. His Military Guide for Young Officers was reprinted in Philadelphia in 1776, and was offered by at least two American booksellers. A derivative work called A New Military, Historical and Explanatory Dictionary, designed as a portable edition to be carried in field baggage, was published in 1782 also in Philadelphia. There is evidence of the use of some of his material as late as the American Civil War.
Thomas Simes had an unremarkable military career, rising only to the rank of Captain, and having seen service in the Duke of Cumberland’s army and possibly in Sardinia. He published his first military text book, The Military Medley, in 1767, and it seems to have been quite popular, going into a second edition the following year. The list of subscribers (people who paid for copies before the book was published) suggests that the author (or perhaps the publisher) was already reasonably well respected; the subscribers included seventeen members of Parliament, two field marshals, twenty generals, and a large number of other officers. His next book, The Military Guide for Young Officers, had over 330 subscribers, and subsequent works had similarly impressive subscriptions.
Simes’ popularity must have been the result of his ability to present a substantial volume of reasonably well-organized information. His material was not innovative, but instead described what had become common practice. Simes borrowed freely and extensively from other European military works. Although this regurgitation of other writings has caused some historians to call him a plagiarist, Simes for the most part credited his sources. He offered value not by introducing anything new, but by compiling and organizing established and accepted principles.
Simes’ books are challenging reading. This is not due to poor authorship, however, as the books are not intended to be read cover to cover. They are reference books, meant to be opened to a particular page when the information on that page is required. They are reasonably well-indexed, especially when compared to similar works by other authors. There is repetition in some of the books, but this is because there is overlap in the topics that each book covers.
Simes’ audience was the career army officer. Simes gives extensive information on the history of warfare and the classical principles upon which the contemporary military discipline was based. He expounds upon matters of military administration and finance. He provides templates of forms for all occasions, from granting furloughs to reporting illnesses. In his books can be found everything that a young officer needed to establish himself in his profession.
He reproduces standard documents, including the clothing warrant of 1768 and the manual exercise of 1764. He provides an overview of the clothing and equipment most useful to officers and soldiers. We know from research that regiments deviated significantly from these recommendations; similarly, officers using these books learned from experience to deviate from them.
Simes discusses many military affairs that might occasionally be useful. Here, again, “occasional” applies to both his contemporary audience and to modern readers. Presentation of colors, honors to high-ranking officers, military funerals, executions, and other infrequent activities are described in sufficient detail. This does not mean that these procedures were always followed exactly. Instead, Simes gives “templates” to be adapted to local needs.
The Military Medley was exactly what the name implied, a compilation of information useful to an officer learning his profession, as well as a reference book on seldom-used procedures. It included a dictionary of military terms (many of the definitions were repeated, albeit expanded, in George Smith’s 1779 An Universal Military Dictionary). Simes’ next book, The Military Guide for Young Officers was essentially an expanded, two volume version of The Military Medley. It capitalized on the success of the Medley, and was the most widely distributed of his works.
His reputation as a military writer firmly established, Simes began writing textbooks for the London military academy run by Lewis Lochée. Lochée himself was a military writer, and Simes followed his example by producing four texts focused on more specific aspects of army discipline. Unlike Lochée and some of the other well-known authors of the era who wrote on topics like military engineering and mathematics, Simes focused on practical knowledge that could be directly applied to everyday operations in peace and war. While none of his later works approached the widespread popularity of the first two, they contain a variety of material that continues to be useful.
It is unfortunate that only a few of Simes’ books have been reprinted, and even those reprints are difficult to come by. They contain much information valuable to the military historian. It is a daunting task, however, to wade through these extensive volumes to cull out the tidbits that pertain to a specific topic of interest. Perhaps someone will compile all of the works into a single condensed volume, composing it very much the way Simes composed his own works, by grouping information from the several books, removing duplication, and indexing it carefully for easy access. Until then, we must be content with the original volumes and microfilm in libraries, the scarce reproductions, or the nth generation photocopies that have been passed on for decades. Regardless of how the information is propagated, the influence of Thomas Simes will no doubt continue for much longer than he himself could have imagined.
Military Books by Thomas Simes
The Military Medley Containing the Most Necessary Rules and Directions for Attaining a Complete Knowledge of the Art (Dublin, 1767); (2nd Edition, Dublin, 1768)
The Military Guide for Young Officers (London, 1772); 3rd edition (London, 1781)
A Military Course for the Government and Conduct of a Battalion (London, 1777)
The Military Instructor for Non‑Commissioned and Private Men of the Infantry (London, 1778)
A Treatise on Military Science which Comprehends the Grand Operations of War and General Rules for Conducting an Army in the Field (London, 1780)
The Regulator or Instructions to Form the Officer and Complete the Soldier (London, 1780)
Compilations or Derivative Works
A Portable Military Library, 4 vols. (London, 1792)
A New Military, Historical and Explanatory Dictionary (Philadelphia, 1782)
The Military Guide for Young Officers (Philadelphia, 1776)
A True History of an Unfortunate Elopement in a Series of Letters by T S, Esq. (London, 1770)
 The information in this article is from Douglas Simes, “Forgotten ‘Expert’: Thomas Simes on the ‘Science’ of War,” WaiMilHist, Univeristy of Waikato, 1998, and from reproductions of Simes’ books.