It was Homer's classic tale The Odyssey that first gave rise to the concept of mentor (Homer n.d.). The story sees its hero Ulysses setting off to wage war. However, before he does, he leaves his royal household, and specifically the responsibility for providing guidance to his son Telemachus, in the hands of his trusted friend Mentor.

By the late 1700's the word mentor became a noun in the English language meaning ‘wise counsellor’. In our modern usage, a mentor is a more experienced person who acts as a trusted friend, counsellor, or teacher (mentorship n.d.).

For more information on the Greek story of Mentor.

Mentoring history and nursing

The nursing profession began its relationship with mentorship in the 1970s when Vance (1977) introduced the concept into the literature. In their work, Vance and Olson (1991) envisioned mentors serving as role models, guides, teachers, coaches, or confidants. The 1990s saw a shift in the way the mentoring relationship was viewed to emphasize its teaching-learning dynamic. In this light, mentorship was also seen as an opportunity for the development and transmission of professional knowledge (Stewart & Krueger, 1996).

The new millennium brought a renewed interest in the concept of mentorship and a call to fully clarify its meaning and application within nursing (Dorsey & Baker, 2004). To this end, the Canadian Nurses Association (CNA) published its Guide to Preceptorship and Mentoring in October 2004. In this document the CNA acknowledged that mentoring was a diverse topic in the way it was defined and used in nursing across the country. The CNA (2004) offered the following definition of mentorship: 'voluntary, mutually beneficial and usually long-term professional relationship'. (p.18.) 

References

Canadian Nurses Association. (2004). Achieving excellence in professional practice: A guide to preceptorship and mentoring. Ottawa, ON, Canada: Author.http://cnaaiic.ca/CNA/documents/pdf/publications/Achieving_ Excellence_2004_e.pdf

Dorsey, D. E., & Baker, C. M. (2004). Mentoring undergraduate nursing students: Assessing the state of the Science. Nurse Educator, 29(6), 260 - 265.

homer. (n.d.). Collins English Dictionary - Complete & Unabridged 10th Edition.
Retrieved November 15, 2010, from Dictionary.com website:http://dictionary.reference.com/browse/homer

Mentor. (n.d.). Online Etymology Dictionary.
Retrieved November 15, 2010, from Dictionary.com website:http://dictionary.reference.com/browse/Mentor

Stewart, B. M., & Krueger, L. E. (1996). An evolutionary concept analysis of mentoring in nursing. Journal of Professional Nursing 12(5), 311 - 321.

Vance, C. N., & Olson, R. K. (1991). Mentorship. Annual Review of Nursing
Research, 9, 175 - 200.