In 1616 Venice had concluded an alliance with France, Switzerland, and the Netherlands against the Habsburgs. So the Spanish ambassador in Venice, the Marquis de Bedmar, started a conspiracy to prepare a naval invasion of the city. The French saved Venice by uncovering the conspiracy though, and the marquis had to leave Venice.
But what if the conspiracy and subsequently the invasion had succeeded? The power balance in Italy would have been destroyed in favor of the Habsburgs. What does this mean for the Thirty-Year War?