Additional land at the northern end of Central Park was purchased in 1859, and the park was completed in 1876. After a period of decline in the early 20th century, New York City parks commissioner Robert Moses started a program to clean up Central Park in the 1930s. The Central Park Conservancy, created in 1980 to combat further deterioration in the late 20th century, refurbished many parts of the park starting in the 1980s.