Sutra period existed roughly between 1000 B.C. to 200 B.C. it is during
this period Brahmins became divided into various Sakhas / branches.
Shakhas means the school from which the students learnt the Ved's and
its interpretations. The teachings of the Rishis are called sutras.
Every Ved has its own sutras. The sutras that contain social, moral
and legal ascepts are called dharma sutras, the sutras that deal with
ceremonials are called Srauta sutras and the sutras containing domestic
rituals are called gruhya sutras. Sutras are generally written in prose
and verse. These sutras are based on Ved's therefore they are known
as Smritis which means remembered.
Dharma Sutra of Shukla Yajur Ved is Shankkhalikita.
Rishi was the most ancient sage of all Brahmin law givers. He was belonged
to Sam Ved School. Gautam's teachings are known as Gautam sutra / Gautam
Rishi was also the author of Dharm Sutra known as Gautam Dharm Sutra
which is the earliest Dharm Sutra containing 28 chapters with 1000 aphorisms.