The Gatha Saptashati (or Gaha Sattasai in Prakrit) is a famous ancient Indian collection of poems.
It is an anthology of seven hundred verses written in the Maharashtri Prakrit language.
The poems primarily deal with themes of love and the lives of common people.
The compilation of this work is traditionally attributed to a Satavahana dynasty king named Hala (or Hāla).
Simuka was the founder of the Satavahana dynasty, but Hala is credited with this literary work.
Therefore, the writer of Gatha Saptashathi was Hala.