The Dinarchy of Antica (not to be mistaken for the offshoot Republic of Antica) was founded on June 17, 2003 by Delphi Augustus and Octavius. Having somewhat misunderstood micronationalism at first, they made a regrettable diplomatic faux pas which severely stunted their early reputation. Despite this, however, they managed to grow into a strong and respected nation, famous for the high average technical competence of its citizens, and for being the birthplace of the prestigious micronational company Zulu 5 Oscar Inc..
Due to the gaps in historical records, it is difficult to determine the exact date the AMI was provided access to the Secret Evil Plans forum. However, unless several forum conversions have screwed up the dates, it was certainly before 31 May 2005. In any case, Antica and Shireroth were close friends for a good while in 2005, and tended to have rather high-quality intelligence on matters like the creation of the Grand Commonwealth.
After several political crises, including a large revolt leading to the creation of the Republic of Antica, and two dinarchs taking office and resigning, the Dinarchy willingly ceded itself to the Imperial Republic of Shireroth on 1 December 2005 by the Treaty of Aquilaria.