What is the Lakshmana rekha, and does it appear in Valmiki’s Ramayana?

A common element of later retellings of the episode of Sita’s abduction is the Lakshmana rekha (line), a protective boundary that is said to have been drawn by Lakshmana around Sita’s hermitage before his departure. It does not appear in Valmiki’s Ramayana. In many of the later versions, Sita remains safe within the boundary, and Ravana can abduct her only after inducing her to cross it. One of the earliest known references to the Lakshmana rekha can be found in the Mahanataka, a Sanskrit work dated between the 10th and 14th centuries.