From the Temple of the Ages, head west, over a small bridge through the swamps, towards the portal into Talmark Wilderness. If you prefer to avoid the swamp area altogether (and less fighting), head south, around the group of Reed Stalkers, until you reach a pathway. Follow this pathway westward. Before getting to the portal, you will see a small tower (see image). Right by the tower you will find Abbot Ramoth, along with a few White Mantle Knights and Justiciars guarding him. Kill Ramoth and he will drop the Litanies of the Unseen. Return it to Brother Mizar for your reward.