 So successful were the 14 comic operas of Gilbert and Sullivan, such as "H.M.S.Pinafore" (1878) and "The Mikado" (1885), that they had a huge influence over the development of musical theatre in the 20th century.This, together with much improved street lighting and transportation in London and New York led to a late Victorian and Edwardian theatre building boom in the West End and on Broadway.