Medieval Christian blockade law distinguished excommunication from mortal sin by intent.

Evidence

If, in ignorance of the law, a man traded in the forbidden things, and if, when he was warned, he recovered the goods he had sold, he was still excommunicated, but the missionaries had authority to absolve him. Similarly a man who became involved, even indirectly, in the forbidden trade, in grave economic need: his case was more serious, but he might be treated leniently. … Men who bound Christians to Muslim employers, as a result of which faith was endangered, were not excommunicated, but had committed mortal sin. The same was true of those who sold Christians as slaves, and even of those who sold Jewish and Muslim women, making them pretend, to the detriment of the Christian name, that they were Christians. There was only occasional licence for close association with Muslims. — Norman Daniel, Islam and the West, 659

Categorization

• DEFINE: Explains the automatic-excommunication mechanism and how the Church graded penalties by knowledge, need, and type of sin.
• XREF: Connects to the sanctions/blockade economics in Milgrom’s law-merchant work and to legal gradation of religious offenses.