The Society for the Encouragement of Arts, Manufactures and Commerce (founded 1754 in London) is the original name of what is now known as the Royal Society of Arts (RSA).
The Society was founded in 1754 by William Shipley and a small group of men who met at Rawthmell’s Coffee House in Covent Garden; their stated aim was to stimulate industry, design, and social progress through prize competitions and public initiatives.  Over time it became a major promoter of innovation and was closely involved in the organisation of the Great Exhibition of 1851 in London.
The Society received a Royal Charter in 1847, and the use of the prefix “Royal” was formally granted by King Edward VII in 1908, giving it its current full name: the Royal Society for the Encouragement of Arts, Manufactures and Commerce (RSA).  Today it functions as a London‑based, multi‑disciplinary institution and charity, focused on social innovation, design, education, and public debate.
From 1774 the Society has occupied purpose‑built premises in central London, now known as RSA House at 8 John Adam Street, Adelphi, WC2N 6EZ.  The building was designed by the Adam brothers (Robert and James Adam) as part of the Adelphi scheme
 
Interesting facts...
perhaps the most important society you never heard of.
The RSA has long been described as a kind of “benign eminence grise” of British public life, quietly underwriting major reforms—planting forests, helping found the Royal Academy of Arts, shaping school examinations, and contributing to environmental movements—without always taking public credit.  Many of its early prize schemes were designed to quietly steer technology and social policy (for example, finding tools to sweep chimneys without children, or ways to foil banknote forgery) while letting others take the spotlight.