To get this achievement you must have found all four chapters of "The History of the Chantry," by Brother Genitivi. This achievement is worth 25G for the Xbox 360 edition of the game and is a silver trophy for the PS3.
All papers have to be found during a single playthrough and, if you miss one in an earlier chapter, there is no way of getting it elsewhere. You can see which papers you have by looking in your journal and selecting the lore tab, the papers are called ‘The History of the Chantry’ and there are four chapters. All of them are found in the Chantry though at different times.
‘The History of the Chantry: Chapter 1’ – Act 1. This paper is located in the upstairs portion of the Chantry and is found on the right side of the room on top of a table. This area is where you find Karl during Anders personal quest.
‘The History of the Chantry: Chapter 2’ – Act 2. This paper is located on the podium where the Grand Cleric is standing on the ground floor of the Chantry.
‘The History of the Chantry: Chapter 3’ – Act 2. This paper is difficult to obtain and it’s recommended to make a save before entering the Chantry during the quest ‘Following the Qun’ because if you miss the small window of opportunity then there is no way of getting it again. This paper is also located on the same podium as the last one but is only there during the quest ‘Following the Qun’ and can only be obtained out of combat, the easiest way to get it is straight after the initial cutscene and before combat or directly after combat before the quest ends. Alternatively, if you bring up the radial wheel during a battle whilst standing at the podium you’ll be able to target the podium and select the paper, picking it up despite being technically in combat.
‘The History of the Chantry: Chapter 4’ – Act 3. The last paper is located on the upper level of the Chantry but this time to the left. The paper is on top of a stack of crates between the bed and the table, you should get this paper early on in the Act as there is a point of no return in the storyline that will bar you from getting it.
After collecting all four papers during one playthrough you will unlock the achievement ‘Chantry Historian.’
