The United States Constitution was first introduced in 1787. Bitter debate about its contents ensued through 1788. The first Congress passed it in 1789. Even then, though, the document was far from finished. Thankfully, the original text included provisions for amendment.
In 1789, Congress passed ten amendments. These ten amendments came to be known as the Bill of Rights.
If anyone ever asks you what the Bill of Rights is, you can begin by saying, It refers to the first ten amendments of the U.S. Constitution.