First inquisition

In other words, guilt was assumed if the person was accused of religious heresy by someone else.

That is a legal issue even to this day many people do not seem to want to talk about. Whether testimony of one accuser can be used as sufficient evidence of guilt.

 

The goal of these laws was to destroy the organization of un-orthodox groups. Their leaders were specially targeted. If a person accepted orthodox faith however he was released.

From the law by Honorius addressed to the proconsul of Africa ( 407 A.D. ), we can read in preamble: to counteract the perverse thoughts of the heretics by appealing to repentance. To this end, forgiveness of the hereticsis set forth, whether they are Donatists, Manicheans or followers of sacrilegious rites of any other belief, with the proviso that they agree to make a confession of faith, that is, that they abjure their deviation. According to the text of the law,repentance stopped any judicial procedure against the heretic.

Legislation was even dangerous for catholic bishops and patriarchs as we can see from the case of Nestorious.
In 428 he addressed the emperor Theodosius II, in his first public sermon, asking him for help to put an end to heretics. In exchange, he committed himself for support to the emperor and defeating the Persians. Seven years later, in 435 the chancery of Theodosius created a new category of heretics, the Nestorians...


So the first christians advocated religious liberty as we can see for example from the writtings of Tertullian.
He wrote in his Apology (around 197 A.D.) that every individual should be free to worship according to the dictates of his conscience:

Let one man worship God, another Jupiter; let one lift suppliant hands to the heavens, another to the altar of Fides; let one — if you choose to take this view of it — count in prayer the clouds, and another the ceiling panels; let one consecrate his own life to his God, and another that of a goat. For see that you do not give a further ground for the charge of irreligion, by taking away religious liberty, and forbidding free choice of deity, so that I may no longer worship according to my inclination, but am compelled to worship against it. Not even a human being would care to have unwilling homage rendered him.

Lactantius wrote pretty much the same in the time of emperor Constantine so the teaching apparently did not change over first centuries. But soon this was changed as we saw from the examples of pope Leo the Great, Augustine of Hippo, emperor Theodosius, emperor Justinian and others...

These first laws about religious persecution later became also the foundations for inquisition. Not all christian states however had such laws, but during middle ages they were forced by popes to accept them as we saw.