 Bishop Hatfield's Hall (later Hatfield College, Durham) was added in 1846 specifically for the sons of poorer families, the Principal inaugurating a system new to English university life of advance fees to cover accommodation and communal dining.The first Durham Miners' Gala was attended by 5,000 miners in 1871 in Wharton Park, and remains the largest socialist trade union event in the world.Early in the 20th century coal became depleted, with a particularly important seam worked out in 1927, and in the following Great Depression Durham was among those towns that suffered exceptionally severe hardship.