There were of course several exceptions to the "five year" rule. The first major exception was that a "derivative" citizenship was granted to wives and minor children of naturalized men. This meant that from the year 1790 to 1922, wives of naturalized men or women who married American citizens automatically became citizens themselves. For nearly 150 years, children under the age of 21 also automatically became naturalized once their fathers gained citizenship. On the other hand, an American woman who married an alien lost her U.S. citizenship, even if she never left the United States! Quick question: Do you know when that regulation was changed?

Here's another exception: according to an 1862 law, honorably-discharged veterans of any war were allowed to petition for naturalization--without previously having filed a declaration of intent--after only 1 year of residence in the United States. An 1894 law extended that same privilege to honorably discharged 5-year veterans of the Navy or Marine Corps. Over 192,000 aliens were naturalized between May 9, 1918, and June 30, 1919, under an act of May 9, 1918, that allowed aliens serving in the U.S. armed forces during "the present war" to file a petition for naturalization without making a declaration of intent or proving 5 years' residence. Laws enacted in 1919, 1926, 1940, and 1952 continued to offer these benefits to war veterans.

Indiana Historical Society