Simple past tense and past participle of confederate.(verb)
Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License
Use "confederated" in a sentence
"It has become a Saudi palatinate, a confederated province of Saudi Arabia, a pocket-size weasel state from which all journalists should in future use the dateline: Manama, Occupied Bahrain."
"Except they re-confederated in 2003, the current flag is based on the confederate national flag."
"Joe Wilson wing nut from the GOP confederated Taliban state of south carolina."