Who were the Federalists and Anti-Federalists?

In the debate over ratification of the Constitution, two
groups emerged.  Those who supported the new Constitution were known as Federalists. 
Those who opposed the new Constitution were known as Anti-federalists. There were
several arguments made by the Anti-federalists against ratification of the Constitution.
First, they argued that the Constitution gave too much power to the national government
at the expense of the states. They also argued that there was no bill of rights.  The
Federalist countered with several arguments of their own. They said that there were
built in safeguards against the federal government becoming too powerful and dominating
the states.  First, there was the idea of separation of powers where the government
would be divided into three separate branches, each with its own powers.  Next there was
a system of checks and balances whereby each branch of government was given the ability
to check the power of the other two branches of government.  And finally, there was the
idea of federalism, where power would be divided between the federal government (that
is, the national government) and the state governments.  Some powers would be given or
delegated only to the federal government, some powers would be reserved to the states,
and some powers would be shared—both the federal government and state governments would
have that power. Perhaps the best known Federalists were John Jay, Alexander Hamilton
and James Madison who anonymously wrote a series of essays that appeared on a regular
basis in four out of five newspapers in New York City.  No one knew who the real authors
were at the time.  The essays, called The Federalist Papers,
explained the reasoning behind the new Constitution and argued for its ratification.
There were 85 essays in all.  In the end, the Federalist prevailed, with all states
eventually ratifying the Constitution.  The Anti-federalists also won a victory when it
was agreed upon to add a bill of rights to the new Constitution shortly after being
ratified.