Which document represents a structured legal framework in ancient Rome?

The Twelve Tables represent a crucial legal framework in ancient Rome, as they were the first attempt to create a codified set of laws accessible to all citizens. Established around 450 BCE, these tables were intended to provide legal protection and ensure that all Roman citizens were aware of their rights and obligations, promoting a sense of justice and accountability within the legal system.

The Twelve Tables covered various aspects of daily life, including family relations, property, inheritance, and crime, thus laying the foundation for Roman law that would influence legal practices for centuries beyond its time. Their public display made the laws known and transparent, which was significant in a society that had largely relied on oral traditions and elite interpretations of the law.

In contrast, the Nicene Creed is a statement of Christian faith, the Edict of Milan is an important decree establishing religious toleration for Christianity, and the Almagest is an astronomical treatise that does not pertain to legal frameworks. Hence, the Twelve Tables uniquely fulfill the question's requirement for a structured legal framework in ancient Rome.