What is the English meaning for kavyam ramayanam krtsnam sitayah caritam mahat?

This is a part of the verse in 4th sarga of Balakanda of Ramayana.

The complete verse is

Kavyam ramayanam krtsnam sitayah charitam mahat,

poulastya vadham ityeva chakara charitavrata.

The gist of the above verse is as follows: this poem was written with the following names, Ramayanam, the great story of Sita, execution/killing of Ravana by the great poet valmaki.

poulastya means pulastya brahma's grandson, Ravana was one of his grandson