"In fact it is comfortable to see the standard of reason at length erected, after so many ages during which the human mind has been held in vassalage by kings, priests, and nobles."
Thomas Jefferson letter to James Madison, December 16, 1786
Jefferson ranked the importance of his "Bill for Establishing Religious Freedom" equal to the Declaration of Independence. The right of the American people to choose their religion now was on parity with their right to choose their own government.
"The life and essence of religion consists in the internal persuasions or the belief of the mind...external forms of worship, when against our belief, are hypocrisy and impiety. "
The Church should be a "voluntary society," Jefferson asserted. It is "voluntary because no man is by nature bound to any church."
"Is a priest to be our inquisitor, or shall a layman, simple as ourselves, set up his reason as the rule for what we are to read, and what we must believe? It is an insult to our citizens to question whether they are rational beings or not, and blasphemy against religion to suppose it cannot stand the test of truth and reason. "
"Truth will do well enough if left to shift for herself. She seldom has received much aid from the power of great men to whom she is rarely known & seldom welcome. She has no need of force to procure entrance into the minds of men, error indeed has often prevailed by the assistance of power or force."
Thomas Jefferson
Source - US Constitution & Bill of Rights Series (Gregory Schaaf, Ph.D.)

Hypatia of Alexandria (355? - 415 CE)
She was the daughter of Theon, a mathematician who taught at the great school at the Alexandrine Library. She traveled widely and corresponded with people all over the Mediterranean. We know of her only through her letters because all of her work was destroyed when the Great Library of Alexandia was destroyed. She taught at the school in the Library in Alexandria, Egypt. Letters written and addressed simply to the philosopher were delivered to her. She taught mathematics and natural philosophy.
She died violently. She was dragged to her death by a mob who pulled her from her classroom into the streets where they peeled her to death with oyster shells.
She wrote that
All formal dogmatic religions are fallacious and must never be accepted by self-respecting persons as final.
Fables should be taught as fables, myths as myths, and miracles as poetic fancies.
To teach superstitions as truths is a most terrible thing.
The child mind accepts and believes them, and only through great pain and perhaps tragedy
can he be in after years relieved of them.
In fact men will fight for a superstition quite as quickly as for a living truth
often more so, since a superstition is so intangible you cannot get at it to refute it,
but truth is a point of view, and so is changeable.
(Source - University of Alabama)