The relative chronology of the two texts is not entirely clear. The text of the Carakasaṃhitā as it survives dates to the Gupta period or roughly to 300-500 CE, which would make it contemporary to or slightly younger than the Sushruta Samhita (SuS). However, the surviving textis considered an edition by one Dṛḍhabala, based on an earlier work of the period of between 100 BCE and 100 CE, so that the bulk of the material in the CS might actually predate the SuS by a few centuries. 
Considered the greatest of all the classical texts on Ayurveda. Written by Caraka, it contains the teachings of the sage Agnivesa, who was one of the six students of the great sage Atreya. It is Agnivesa’s teachings which makes up the bulk of what is known about classical Äyurveda. Caraka was himself a great physician.