Gratian's purpose and puzzles in Causa 14 (13)?

1. Training lawyers to make arguments in court?  The arguments are incomplete.

2. Demonstrate that legal texts trump biblical arguments? 

3. Illustrate the tension between parties in a courtroom?

4. Purely a teaching device to introduce students to the courtroom?

5. Why did he not refer to key texts in Causa 16 q.4?

6. Is this a real case?  Did Gratian participate as an advocate?  Judge?

K÷ln, Erzbisch÷fliche Di÷zesan- und Dombibliothek 129, fol.  165r