When was the Constitution written?

Why this is the answer

1787. That is the year the Constitution was written, and the system it created is the one still in use. James Madison was its main author, and he later became the fourth president. The document itself is short, a preamble and seven articles, and it has been amended twenty-seven times since. Do not confuse writing it with putting it into force. Ratification by nine of the thirteen states was required; Delaware ratified first on December 7, 1787, New Hampshire was the ninth in 1788, and the Constitution took effect on March 4, 1789, when Congress met for the first time. By 1790 all thirteen had ratified. Memory hook: written in 1787, in force in 1789, eleven years after 1776.