1810 ca. Full Dress Jacket, Lothian Yeomanry Cavalry, Britain. The East Lothian Yeomanry Cavalry was raised as a one troop formation at Haddington in May 1797. Five years later a second troop was raised and in 1803 a third and fourth troop. The regiment was reduced to one troop in 1823 and disbanded 15 years later. National Army Museum, London, UK.   https://books2read.com/SuziLoveFashionMen1800-1819 In Jane Austen’s time, or the early 1800s, gentlemen were seen in military coats like this often because many Englishmen were involved in the long lasting wars against Napoleon. .

1804 Men’s Fashions In The Time Of Jane Austen. From the finish of the 18th century until 1820, men’s fashions in European and European-influenced countries moved away from the formal wear of brocades, lace, wigs and powder to more informal and relaxed styles. Focus was on undress rather than formal dress.  Typical menswear in the early 1800s included a tailcoat, a vest or waistcoat, either breeches, pants, or the newer trousers, stockings, shoes or boots, all worn with an overcoat and hat. This basic ensemble was accessorized with some form of neckcloth or cravat, gloves, walking stick, cane or riding crop, handkerchief, fobs, watch and perhaps a quizzing glass or eye glass. 

In 1806, the Journal des Dames et des Modes stated, ‘The informal outfit for a young man includes a coat of similar style, snug pantaloons which are probably knitted, and a striped waistcoat.’ 

Skirted coats were replaced with short-fronted, or cutaway, tailcoats worn over fitted waistcoats and plain, white linen shirts. Knee breeches were gradually replaced by tight-fitting pantaloons and later trousers, decorative shoes with buckles were replaced with a variety of boot styles, and fussy and ruffled neckwear gave way to intricately tied, white linen neck cloths. A Regency Era, or early 1800s, gentleman was outfitted in more practical fabrics, such as wool, cotton and buckskin rather than the fussy brocades and silks of the late 1700s.