How long is the longest existing family tree?

The "longest family tree" claim is obviously a prestigious one, and many clans — mostly of the royal variety, because they're the most obsessively documented — have laid claim to it over the years. But only one tribe has been able to make it stick, and its members have gone to great lengths to do so. In 2005, the Guinness Book of World Records recognized the Confucius genealogical line as the longest family tree in history, with 86 recorded generations over 2,500 years. The Chinese philosopher (551 to 479 BCE) is thought to have 3 million descendants all over the world [source: Zhou].

In 2009 the family-run Confucius Genealogy Compilation Committee (CGCC) published the fifth edition of the "Confucius Genealogy," a decade-long effort of staggering proportions. It's an 80-volume set that contains the names of more than 2 million of these descendants. The Confucius line is so well-documented because of the prestige (and honorary titles and positions) historically associated with being a Confucius descendant.

The first "Confucius Genealogy" was published in 1080. The fourth edition, printed in 1937, contained 600,000 names [source: Zhou]. For the latest project, the CGCC set up 450 branches all over the world and signed up more than 1.3 million new descendants. The committee also made the game-changing decision to include women, ethnic minorities and overseas descendants for the first time, which obviously increased the registration numbers exponentially [source: Zhou].

Times have changed, but the family's documentation methods — somewhat amazingly — have not. The CGCC administered no DNA tests to any of the newest registered descendants. All that was needed was a paper trail and 70 cents for inclusion into the registry. The DNA technology is readily available, but experts contend that the Chinese people are still more interested in the traditional system. The CGCC also probably balked at the expense of testing each one of those 1.3 million people. And if any of the descendants were found to be incorrectly included, the potential damage to the family name — not to mention the paperwork — would have been devastating.

The Confucius clan survived the contention of another group to the family-tree crown in 2008. Two German men made international news when it was discovered that they were the descendants of a genealogical line that spanned 120 generations. But the "longest family tree" title splashed across the headlines wasn't quite accurate. They had been found to be directly descended from 3,000-year-old Bronze Age bones found in a local cave, which did make their caveman ancestor more ancient than Confucius. But the actual family tree isn't completely filled out — there are many blank generations.