The Treasure from the Past / Warhorse Gear was a Pre Order Bonus which can now be bought for a Small Sum.

The Guide will use a Text Description and Multiple Screenshots in a Left to right Order to explain where the Treasures are. Click the Screenshot's to enlarge them.

I recommend getting this Set when you are around the areas where the Treasures are during the Course of the Main Quests or after the Battle of Pribyslawitz or after the Battle of Vranik for Sure.
Its Possible to get all of them right after the Intro to my Understanding but 2 are locked inside Chests, 1 Easy and 1 Very Hard and 2 require a Shovel.
If you get the Whole Set too early in the Game it can be Overpowered and look out of Place.

Keep in Mind that
The Lords of Leipa Set which you get from the Tourney of Rattay outclasses this Set. But you can only get a Piece at a Time and the Fights can be challenging Early to Midgame.

Ancient Map I leads to a Treasure East of Rattay and Southeast of Neuhof. Behind a Unmarked Camp inside the Forest and past the Point of Interest which is a Burned down House there is a Burried Treasure, for this Treasure you need a Shovel.
The Loot besides the Warhorse Gear might be level related and from a Loot Table.

Ancient Map II leads to a Treasure Far South West of Rattay and South of Vranik. Inside the Forest just below a Giant Rock insde a Mine Entrance.
The Loot besides the Warhorse Gear might be level related and from a Loot Table.

Ancient Map III leads to a Treasure North of Uzhitz. Its by the end of a Stonewall below a Big Tree burried. For this Treasure you need a Shovel.
The Loot besides the Warhorse Gear might be level related and from a Loot Table.

Ancient Map IV leads to a Treasure West of Rattay inside a Stone Ruin inside the Forest. You need to go trough the Door and walk up the broken Wall on the backside to get inside, the Treasure is inside a Locked Chest with the Difficulty Easy.
The Loot besides the Warhorse Gear might be level related and from a Loot Table.

Ancient Map V leads to a Treasure Northwest of Skalitz inside a Forest, right beside a Deer Hunting Spot by a abandoned Wooden Cabin. Its inside a Locked Chest with the Difficulty Very Hard.
The Loot besides the Warhorse Gear might be level related and from a Loot Table.