Weynon Priory (Quest)

Walkthrough
After you shut the gate to Oblivion in Kvatch, take Brother Martin to Weynon Priory just southeast of Chorrol. There, you will be confronted with Mythic Dawn Agents. Fight them and then go to the small tower at the right to find Jauffre fighting against three Mythic Dawn warriors.

After you save him, Jauffre wants to check if the Amulet of Kings is still where he hid it, so follow him into the building. You'll discover that it's gone and that you need to recover the amulet.

Jauffre suggests bringing Martin to the Cloud Ruler Temple sanctuary northwest of Bruma. Head there and ten Blades will welcome you and the heir. They will declare him emperor and Martin will give a short impromptu speech. He'll then discuss with you daedric magic and the importance of the Amulet of Kings.

Talk to Jauffre and he will ask you to join the Blades. If you join, you will have free access to a multitude of books, armor, weapons, and gold in the sanctuary.

Jauffre will then give you the next quest, 'Path of Dawn, and will ask you to go talk to Baulus located in Imperial City to see if he has uncovered any knowledge regarding the emperor's assasination.