In the late 19th century the landscape architect Samuel Parsons took the position of New York City parks superintendent. A onetime apprentice of Calvert Vaux,[153] Parsons helped restore the nurseries of Central Park in 1886.[154] Parsons closely followed Olmsted's original vision for the park, restoring Central Park's trees while blocking the placement of several large statues in the park.[155] Under Parsons' leadership, two circles (now Duke Ellington and Frederick Douglass Circles) were constructed at the northern corners of the park.[156][157] He was removed in May 1911 following a lengthy dispute over whether an expense to replace the soil in the park was unnecessary.[155][158] A succession of Tammany-affiliated Democratic mayors were indifferent toward Central Park.[159]