There are some bards that revel in irresponsibility and see life as one huge, hedonistic party. You’re not one of those. You have a role somewhere between “priest” and “historian” and act as a caretaker of the important cultural memories and tales of your society. You may still enjoy a good wild party now and then, but achieving this level of training requires a serious investment of time and some harrowing tests, and it is unlikely you want to treat all of that effort and hardship casually.
When you select this archetype at level 3, you gain proficiency with the History, Culture, and Religion skills. If you are already proficient in any of these skills, you gain an expertise die to any that apply. You also learn the shillelagh cantrip and the ceremony spell. Both count as Bard spells for you, but neither counts against your cantrips or spells known.
Also at 3rd level, you are continually under the effect of the comprehend languages spell. This is a magical effect and can be suppressed if you are in an antimagic field or similar effect, but it reactivates with no action required on your part as soon as you are outside the area of the suppressing effect. In addition all spells from the knowledge school are added to the bard list for you, and you may select from them when learning a new bard spell.
At 6th level, your study into the old tales has turned up some useful tricks. You learn an additional battle hymn of a level that you could normally perform. Whenever you finish a short or long rest, you may exchange this battle hymn for a different one of a level you could normally perform.
At 14th level, you learn to tap into the collective memories of all the mortals on the plane you occupy. As an action, you may do one of the following:
The new knowledge persists until you use this ability again or until you begin a long rest. Once you have used this ability a number of times equal to your Charisma modifier (minimum once), you can’t do so again until you finish a long rest.