The Grand Duke of Flandrensis announced his intention to resign on 11 September, on the grounds of personal reasons and growing inactivity of the organization, initiating the election of a new leader. On 15 September, Yaroslav Mar was announced the elected Administrative-General.
In his inaugural message, Yaroslav Mar raised the issue of the lack of a contemporary claims' map, promised to conduct a cleanup of inactive members, and to extend the AMU's presence on the Internet, in particular by developing a proper website and reforming the Facebook page of the organization.
The Grand Duke of Flandrensis has been leading the AMU since 2009, almost since the organization's foundation, and is considered the Father of Belgian micronationalism. A Russian violinist, Yaroslav Mar is the incumbent President of the Federal Republic of Lostisland and Flandrensisian Ambassador to the Eastern Europe. In the past, Yaroslav Mar has leaded micronational organizations such as the Single Union, the League of Russophone Micronations, the Inter-Micronational Treaty Organization and the Grand Unified Micronational. Yaroslav Mar is the General Sponsor of the Inter-Micronational Chess Federation, a governing body for micronational chess; in recognition of merits, he was awarded with numerous micronational titles, such as the Knight Grand Commander in the Order of Flandrensis, Knight in the Austenasian Order, Honorary Knight of the Sovereign Military Roman Hadrian Order and others.