Rhazes, also known as Al-Razi, was a prominent Persian physician and philosopher who lived during the Islamic Golden Age, around the 9th century. He is best known for his contributions to medicine, particularly in the field of pediatrics and ophthalmology. Rhazes was one of the first to distinguish between smallpox and measles, significantly advancing the understanding of infectious diseases. In addition to his medical work, Rhazes authored numerous texts, including the influential book Kitab al-Hawi, which compiled medical knowledge of his time. His emphasis on observation and experimentation laid the groundwork for modern scientific methods in medicine, making him a key figure in the history of healthcare.