The Seminary was a sister institution to the East India Company College in Hertfordshire, which trained civilian "writers" (clerks).

Addiscombe Place, the mansion house which formed the central building of the later Seminary, was erected in about 1702 by William Draper, on land which he had inherited in 1700 from his aunt, Dame Sarah Temple.

Its interior included many mural paintings of mythological subjects, supposed to be the work of Sir James Thornhill; while high up on the exterior east front was carved the Latin inscription, Non faciam vitio culpave minorem ("I will not lower myself by vice or fault").

[3] Following the death of Lord Liverpool in December 1808, Addiscombe Place was put on the market by Emelius Delmé-Radcliffe (Clarke's brother-in-law).

[9][1] Cadets or their families were required to pay fees (£30 a year when the Seminary first opened; £50 a term by 1835), but these were heavily subsidised and represented only a proportion of the true costs of their education.

[12] The curriculum comprised instruction in the "sciences of Mathematics, Fortification, Natural Philosophy, and Chemistry; the Hindustani, Latin, and French languages; in the art of Civil, Military, and Lithographic Drawing and Surveying; and in the construction of the several gun-carriages and mortar-beds used in the Artillery service, from the most approved models".

[13] The Company paid well, and attracted some distinguished academic staff: John Shakespear published a standard Hindustani grammar, and Jonathan Cape was a Fellow of the Royal Society.

Examinations were held twice-yearly in June and December: they lasted about three weeks, and culminated in a Public Examination, a day-long affair of some ceremony before a distinguished invited audience, which included orchestrated demonstrations of book-learning and of military exercises such as swordsmanship and pontoon-building; an exhibition of drawings and models; a formal inspection; and the distribution of prizes.

[23] The Public Examiner, who presided, was an eminent general (see list below); while the audience usually included some of the Directors of the East India Company, and often the Archbishop of Canterbury, who had a residence nearby at Addington Palace.

However, the War Office decided that the establishments at Woolwich and Sandhurst were sufficient for their needs, and the college closed in June the same year.