How did the Basilica of Leo VI update Justinian's legal code?

The Basilica, a 9th-century legal code initiated by Basil I and completed under Leo VI, updated the 6th-century Code of Justinian by addressing its internal inconsistencies, repetitiveness, and lack of systematic organization.12

While Justinian’s work consisted of four separate collections where subjects were often treated in multiple, disparate places, the Basilica integrated these provisions into a single, orderly work written in Greek. Leo VI’s commission of lawyers reexamined the earlier code to remove obsolescent, conflicting, and superfluous items, ultimately expanding the work to 60 books.12

The Basilica synthesized parts of Justinian’s Codex and Digest, while incorporating material from the Novels and subsequent imperial ordinances. By clarifying and simplifying these laws, the Basilica resolved the uncertainty that had long plagued imperial judges and established itself as the foundation of Byzantine jurisprudence.21