Cause:
From 1789, the date of the first conspiracy against Spain, down to 1857, when a Constitution was promulgated, Mexico was in a state of permanent warfare. In 1861 France, Spain, and Great Britain adopted joint measures against the republic in order to get better protection for their subjects and their property. In 1862 Great Britain and Spain withdrew. But Napoleon III conceived the project of establishing a monarchy in Mexico under his patronage, and so increasing French ascendancy beyond the Atlantic.