Grandmaster Writs

Once you have destroyed Dagoth Ur and have been promoted to Grandmaster, you may speak with any of the remaining Morag Tong quest-givers to find that there are four new writs to be executed: Larrius Varro (Imperial Legion), Baladas Demnevanni (House Telvanni), Dram Bero (House Hlaalu), and Mistress Therana (House Telvanni). These are TOUGH writs to execute, not only because the targets are worthy opponents in their own rights, but because your reputation with each of these factions will take a serious hit.

You may have already taken out Therana as part of the Main Quest (not being the most mentally stable individual, it might have been easier to take her out than to gain her support to be named Telvanni Hortator). If so, collect your 4,000 golds and count your blessings.