The Golden Age of Rubble Adventuring was 1625-1626, after the Lunar Occupation of Pavis was ended. Argrath, a former adventurer himself, encouraged the restless adventurers and mercenaries that followed him to explore the Big Rubble and retake its treasures.
Bands of adventurers, supported by the ruler, raided areas long considered too dangerous for explorers, such as Blind King Hill, Griffin Gate, Ogre Island, and even the Troll Stronglands. Manside became considerably safer, and its human population grew significantly, and several fortified inns/trading posts catered to these adventurers.
Many treasures from the Second Age were reclaimed, including EWF and God Learner artefacts. It is said that Balastor’s Axe was reclaimed as well, although I have heard of at least a dozen different claimants to the deed (including even a dark troll!).
Some scholars believe the nucleus of what became the Sartar Magical Union was founded in these years, by bands of heterogeneous adventurers who learned to work together and were taught additional magical secrets by Argrath. When Argrath left Pavis for Dragon Pass at the end of 1626, most of these adventurers followed him, leaving a very different Old Pavis behind.
If we think about the Big Rubble as being over 20 square km of ruins and underground chambers, it can be thought of as a vast mega dungeon that is larger even than such D&D legends as Rappan Athuk or Castle Greyhawk. Or about the size of the ruins of Boston in Fallout 4.
