Traditional sources attribute to Khyung po rnal 'byor, the founder of the Shangs pa bka' brgyud lineage, a lifespan of 150 years beginning in a tiger year, usually thought to be 978 or 990. A careful examination of the chronological indications given in his rnam thar, however, suggest that it is implausible to hold that Khyung po was born prior to the middle years of the eleventh century. The present communication surveys the relevant evidence for Khyung po's dating, and demonstrates the reasons for which traditional historians regarded his career as beginning a full half century or more earlier than it actually did. It will be seen that the questions raised here are pertinent to the larger problems surrounding the "authenticity" of Shangpa origins overall. (Than Garson 2005-09-22)