Rowntrees is an English confectionery business based in York. Rowntree developed the Kit Kat (introduced in 1935), Aero (introduced in 1935), Fruit Pastilles (introduced in 1881), Smarties (introduced in 1937) brands, and the Rolo and Quality Street brands when it merged with Mackintosh's in 1969 to form Rowntree Mackintosh Confectionery.