A large material chest is an item in Evony TKR (The King's Return).
The description of Large Material Chest in Evony TKR says:
Open to receive one or two Equipment materials.
Large Material Chest is known to potentially be obtainable from opening Senior Spring Festival Rewards, Medium Spring Festival Rewards, Lv12 Boss Monster Chest, Lv13 Boss Monster Chest, Senior Lava Turtle Chest, Senior Golem Chest, Senior Witch Chest, Senior Warlord Chest, Lv14 Boss Monster Chest, Lv15 Boss Monster Chest, Legendary Lava Turtle Chest, Legendary Golem Chest, Legendary Witch Chest, Legendary Warlord Chest, Epic Golem Chest, Epic Witch Chest, Grand Ymir Chest, Super Ymir Chest and Legendary Ymir Chest. The links for each item are below:
Note: This list may be incomplete.