Portraits of 19th century children in tartan plaid. Made fashionable by the children of Queen Victoria and Prince Albert, in no time children around the world were dressed like little Scots highlanders whether they were or not.

"Children of John and Mary Ross." 1843.
“Children of John and Mary Ross.” 1843. American. Samuel Bell Waugh, artist (1814-1885). Image ¬©Gilcrease Museum. Fair use license. via https://collections.gilcrease.org/object/01261220
"Portrait of young Harry Herbert Keith." ca. 1860.
“Portrait of young Harry Herbert Keith.” ca. 1860. American school. In the public domain due to age. via https://www.curiousandunusualtartans.com/portraiture
"Portrait of a Young Boy, Wearing Highland Dress." 1892.
“Portrait of a Young Boy, Wearing Highland Dress.” 1892. French. Charles Henri Hilaire Michel, artist (1817-1905). In the public domain due to age. via https://www.curiousandunusualtartans.com/portraiture