Vanity Fair Mills, Inc. (Mills) (plaintiff) was an American company that manufactured and sold women’s underwear under the registered trademark “Vanity Fair” in the United States since 1914, and in Canada since 1917. The T. Eaton Co., Ltd., (Eaton) (defendant) was a Canadian retail company that offered women’s clothing under the mark “Vanity Fair” in Canada. Eaton was granted registration of that mark for women’s clothing in Canada in 1915, but was denied registration for women’s underwear in 1919 because of Mills’ prior registration. Between 1945–1953, Eaton stopped using the Vanity Fair mark itself and instead purchased and sold Mills’ branded goods in its retail locations. In 1953, however, Eaton began again using the mark for its own goods, and sold both Mills’ goods and its own cheaper goods under the same mark. According to Mills, Eaton also advertised and sold its goods bearing the Vanity Fair mark to United States consumers through the mail. Mills sued Eaton in United States federal court alleging trademark infringement and unfair competition in both the United States and Canada, and seeking an injunction against Eaton using the Vanity Fair mark for women’s underwear in both Canada and the United States. The district court held that the American and Canadian issues were intertwined and that it had no jurisdiction over the Canadian issues. The court dismissed the complaint and gave Mills leave to file an amended complaint stating only the American-based claims. Mills appealed the judgment dismissing the complaint.