The Grand Alliance was a coalition of star nations opposed to the Solarian League, created in the year 1922 PD. Its creation was the result of the revelation that many of the major political and military events in the recent history of these nations had been influenced by the enigmatic Mesan Alignment in order to take over the colonized universe.
After learning of this, courtesy of Anton Zilwicki and Victor Cachat, President Eloise Pritchart sailed to Manticore to offer a peace treaty and military alliance to Queen Elizabeth III. The Queen agreed, and over the next month a rough treaty was drafted and subsequently confirmed by the Manticoran and Havenite legislatures. (HH12, HH13)
Treaty of Alliance
The Grand Alliance was formed on the basis of a de facto peace treaty between the Republic of Haven and the Manticoran Alliance members that ended the Second Havenite-Manticoran War. Both sides gave up currency repatriations, Haven admitted its diplomatic correspondence before the war was forged by Secretary of State Arnold Giancola, and Manticore returned warships captured during the First Battle of Manticore. (HH13)
Known star nations participating in the Grand Alliance were:
The Kingdom of Torch's relationship to the Grand Alliance was unknown, though probably friendly. In addition, both the Republic of Erewhon and the Solarian League's Maya Sector were cautiously cordial towards it, although the latter found it politically prudent to keep friendly ties unofficial.
Although the Andermani Empire was a member of the previous Manticoran Alliance, on the advice of Honor Harrington and Queen Elizabeth III, it chose not to join the Grand Alliance to leave open the potential for independent action against the Mesan Alignment. (HH13)
One of the first actions of the Alliance was the formation of the Grand Fleet, a force of military units from several member nations under the overall command of Admiral Honor Alexander-Harrington. It first saw action in the Second Battle of Manticore, which resulted in an overwhelming victory for the Alliance forces. (HH13)