Phandelver Pact

Ancient pact between Dwarves, Gnomes, and Humans to mine Wave Echo Cave in peace.
Over five hundred years ago, a pact was made between a clan of gnomes and dwarves which became known as the Phandelver Pact. Together they mined the magically rich ores within Wave Echo Cave. Human spellcasters from nearby Phandalin joined forces with them and together they combined their collective skills to create a forge to craft magical items dubbed the Forge of Spells.
Everything came to an abrupt end when orcs, craving magical treasures, sieged Phandalin and the Wave Echo Cave mine. The battle destroyed Phandalin and much of the mine as well, causing various cave-ins throughout. Very few survived the conflict to relate the tale. The Forge of Spells become legend and the entrance to Wave Echo Cave was lost.