The Kingdom of Ealdormere officially came into being on October 24th, 1998, or as referred to in the Society for Creative Anachronism, A.S. (Anno Societatis) XXXIII (33). On the day that it was created, the border's contained all of the Province of Ontario, except Essex County. Within a year of becoming a Kingdom negotiations had been completed to transfer the area including Postal Code Regions P0Y, P0X, P0V, P0T and P0W (including the cities and towns of Thunder Bay, Kenora, Dryden, Souix Lookout and Fort Francis to the Principality of Northshield (now the Kingdom of Northshield) and the Middle Kingdom).

However, the Kingdom of Ealdormere unofficially began in January of 1998 at the Winter Board of Directors Meeting in California, when the Board voted to approve the application for Kingdom status from the Principality of Ealdormere, during the reign of Prince Gunther and Princess Morgon, with the blessings of King Palymar and Queen Aislinn of the Middle Kingdom. Present at the Board Meeting were Viscount Sir Menken Brechen (Board member) and Viscountess Moria the Black (Principality Seneschal). The bid was discussed over a period of 5 hours that day, being put forward and tabled 3 times before being passed, a move that surprised many of the people at the meeting as it was believed the agenda item would be dealt with quickly and the passage was a foregone conclusion. However, due to difficulties with the Canadian Postal Code system and the system that was currently being used to sort Kingdom newsletter labels, agreements and changes to procedures had to be arrived at throughout the day to address the concerns of the Society office and the Society Seneschal before the motion could be passed.

In order to accommodate the schedule agreed to at that Board meeting, the last Heirs to the Principality of Ealdormere, Berus and Marion were invested 2 weeks early, in March of 1998, and became Prince Berus Wolfsun and Princess Marion FitzWilliam, who presided over the first Crown Tournament for the Kingdom of Ealdormere on April 4th, 1998 (A.S. XXXII), in the Barony of Ramshaven. The Finals of the Tournament were between Earl Syr David Martin of Failsworth fighting for Viscountess Elina de Braose and Malik 'abd al-Rahman, Baron of Rising Waters, fighting for his Baroness, Genevieve Chastellain D'Anjou. At the end of the day, Earl Syr David was victorious, however, as there was technically no Kingdom to speak of, he and his consort were invested simply as the 'Heirs' of Ealdormere, and bore the titles 'Heir and Heiress to the Kingdom of Ealdormere'. On October 24th, 1998, King David the Greater, and Queen Elina de Braose were crowned at Merritt Hall in the Barony of Ben Dunfirth, the Kingdom Laws were read into Regents Courts throughout the day, and the Kingdom of Ealdormere came into existence.