Jesus the Christ is the famed Jesus of Nazareth, the Jewish King, Messiah (Prophet according to many of those who are presently Jews), and spiritual teacher. Jesus is mentioned repeatedly over the course of the book. Rumi felt a deep connection to Jesus and enjoyed using Him and moments of his life story as a point of reference in many of his poems.
Most readers have at least heard of Jesus the Christ of the Jews. The extent of knowledge that any given reader has about the individual's earthly life is not clear. A great deal has been written about Jesus' life and work prior to his resurrection. There is very little written work about his life after his resurrection. Finally, he is so much more talked about, prayed to and criticized or referred to during bouts of irritability that it is safe to think that while readers have probably at least heard of him, their levels of knowledge and intimacy with this divine incarnation is not presumed to be identical for every reader.
The Essential Rumi