Why did Paul Ehrlich Discover syphilis?

Paul Ehrlich did not discover syphilis; the disease was identified earlier, with notable contributions from Giovanni Maria Lancisi in the 18th century and others. However, Ehrlich made significant advancements in the field of immunology and chemotherapy, notably developing the first effective treatment for syphilis, Salvarsan, in 1909. This compound marked a breakthrough in the treatment of Infectious Diseases and showcased Ehrlich's pioneering work in targeted therapy.