It is important to understand the natural history of untreated syphilis. All patients with primary disease will progress to secondary disease; about a quarter will then recover spontaneously. Of the remaining patients who go on to latent syphilis, about 40% will have a relapse of secondary syphilis, generally within the first year. Over years, about 60% will continue to be latently infected and about 40% will go on to develop late manifestations of syphilis. Those late manifestations will cause incapacity and death in about 1/3 of those who were infected to begin with.