Eleventh Amendment to the United States Constitution

The Eleventh Amendment (Amendment XI) to the United States Constitution was passed by Congress on March 4, 1794 and ratified by the states on February 7, 1795. It deals with each state's sovereign immunity and was adopted to overrule the U.S. Supreme Court's decision in "Chisholm v. Georgia".
Lawsuits against states.
The idea of sovereign immunity originated in English common law. It was also proposed by political theorists like Thomas Hobbes and Jean Bodin. The founding fathers of the Constitution were aware of the traditional doctrine that states were immune from private lawsuits. Several Anti-Federalists were afraid that Article III, Section 1 of the Constitution, which declares that the federal judicial power extends to suits "between a State and Citizens of another State", would override that doctrine. 
The Eleventh Amendment was a direct reaction to an unpopular ruling by the Supreme Court in "Chisholm v. Georgia" (1793). In "Chisholm" the Court said federal courts had the power to hear lawsuits brought by citizens against US states. Also, that states were not immune to these cases. The Eleventh Amendment reversed this decision and does not allow cases brought against a state by a citizen of another state or country. It says nothing about a citizen bringing a suit against their own state.
In "Ex parte Young", the Supreme Court decision allowed suits in federal courts against officials acting on behalf of states of the union to proceed despite the State's sovereign immunity, when the State acted unconstitutionally.
The Eleventh Amendment is one of five amendments that overturned earlier Supreme Court decisions.