Bill of Rights Day is observed on December 15, 2021. The Bill of Rights is the collective name for the first ten amendments to the United States Constitution. Proposed to assuage the fears of Anti-Federalists who had opposed Constitutional ratification, these amendments guarantee a number of personal freedoms, limit the government's power in judicial and other proceedings, and reserve some powers to the states and the public.
The amendments were introduced by James Madison to the 1st United States Congress as a series of legislative articles. They were adopted by the House of Representatives on August 21, 1789, formally proposed by joint resolution of Congress on September 25, 1789, and came into effect as Constitutional Amendments on December 15, 1791, through the process of ratification by three-fourths of the states. The Bill of Rights had little judicial impact for the first 150 years of its existence, but was the basis for many Supreme Court decisions of the 20th and 21st centuries. (With material from: Wikipedia)