The first phase of Pallavan architecture from 610-690 AD saw the development of rock-cut cave temples known as mandapas at Mahabalipuram. These included early experiments with pillared halls and structural prototypes like the Rathas that served as models for later temples. Key features included the beginnings of the Dravidian column with elements like the lion capital, and the use of reliefs to combine sculpture with architecture. This phase established foundations for the evolution of the temple architecture in the Dravidian style.