What is the supreme law of the land, in what year was it written and how many changes have there been to it?

   The Supreme Law of the Land is the Constitution that sets up the government and self-government and that no one is above the law, but then the law is for the people. "We the people". Also it is the fundamental framework of America's system of government.
   The Constitution was written and signed in Philadelphia in the Assembly Room of the Pennsylvania State House, now known as Independence Hall. It was written during the Philadelphia Convention. Which convened from May 25th to September 17, 1787. It was signed on September 17, 1787.
   Even though of 11,000 attempts to amend the U.S Constitution, only 27 were amended successfully. 

Ibelieve the answer is 1756.