Ventani II was the birthplace of Tret Akleen, who is considered the founder of the modern Cardassian Union. In the 24th century, the Ventani system is located along the border between the Union and Federation.
When Captain Benjamin Sisko began planning the invasion of Dominion-held territory in late 2374, Elim Garak suggested Ventani II as the first target, seeing such an offensive as dealing a blow to Cardassian morale. This suggestion was ultimately rejected because the planet was of little strategic value to the Dominion. (DS9: "Tears of the Prophets" deleted scene)
Several months later, a group of Human Augments led by Rhys Darcen planned to contaminate the atmosphere of Ventani II with a biological weapon, even though that would result in the deaths of thousands of civilians. Darcen believed that such a strategy against Ventani and other Cardassian colonies would discourage the Cardassian people from continuing to side with the Dominion in the Dominion War. The attack was eventually halted by the combined efforts of the USS Lambda Paz and Klingon warships from the Ninth Fleet. (Star Trek: Lambda Paz: "Religion To Do Good", "A Cause of Greater Worth")
During the Ninth Fleet's efforts to draw Dominion and Cardassian forces away from the Ventani system, Gul Latham noticed that Ventani was left vulnerable as a result of the hit-and-run offensives. His request to his Vorta counterpart Diralna for Dominion reinforcements was denied, however. Diralna noted that Ventani II was a strategically worthless planet and the only monuments Cardassia would need would be those commemorating a Dominion victory. ("A Cause of Greater Worth")