The latency period of tertiary syphilis is not clearly defined, but it is certain that once tertiary syphilis appears, the duration of illness in patients generally exceeds two to three years, meaning the latency period is at least two to three years long. Of course, some patients may reach five to ten years. This depends on each individual's resistance as well as the virulence and amount of the virus. Additionally, if one contracts tertiary syphilis, it is crucial to seek timely and proper treatment, as it may be life-threatening.