The longest family tree in the world is that of the Chinese philosopher and educator Confucius (551-479 BC), a descendant of King Tang (1675-1646 BC). This tree spans more than 80 generations and includes over 2 million members. The House of Grimaldi has been ruling Monaco since the 12th century, with Albert II, Sovereign Prince of Monaco, as its current head. The royal dynasty of Casa Grimaldi began in 1297, when Francesco Grimaldi took over the lordship of Monaco along with his soldiers dressed as Franciscans.
The House of Oldenburg originated in the 12th century with Elimar I, the first Count of Oldenburg. However, it was only in the 15th century that Christian I became king of Denmark and the family fathered several kings of Norway, Denmark and Sweden. The descendants of Austria's most prolific and powerful family, the House of Habsburg (now the House of Habsburg-Lorraine), still hold a prominent position in Austrian society and politics, even though Austria no longer has a royal family. The main line of the family through male heirs is technically dead, but the lineage continued through Maria Theresa, who was the Empress of the Holy Roman Empire in the 18th century.
In the 14th century, a descendant of Confucius moved to Korea and changed the family name from Kong to Gong to make it Korean; currently there are more than 34,000 descendants of Confucius living in Korea. Ethiopia is no longer a monarchy and its imperial family hasn't ruled since 1974, yet the House of Solomon still exists today. Its lineage dates back to Menelik I, son of King Solomon and Queen Sheba. The last emperor of Ethiopia, Haile Selassie I, died under mysterious circumstances a year after the 1974 coup; his descendants are still alive and Selassie's grandson, Zera YJacob Amha Selassie, is the Crown Prince of Ethiopia (in exile).
The Lurie family is a strong candidate for being the oldest known family tree in the world. Neil Rosenstein wrote The Lurie Legacy which states that this family can trace their lineage back to King David from the Bible. While there is some vague historical evidence that King David was a real historical figure, it is uncertain whether he was or not. Rosenstein's book provides much evidence that this family tree dates back to 13th-century France.
The Lurie family is considered to be one of the most prominent Ashkenazi Jewish families in history and many notable historical figures come from this family such as Karl Marx, Sigmund Freud, Felix Mendelssohn, Martin Buber, Rashi and Hezekiah. The Donnellys are said to be the oldest family in the world with more than 1000 years between them. Scientists have compiled a 5,700-year-old family tree from human bones buried in a grave in Cotswolds, United Kingdom. This tree is believed to be one of the oldest known family trees in existence. Most royal families need to prove their lineage and their right to rule by tracing their ancestry back several centuries. Some even claim to be descended from biblical figures.
Monaco is one of the richest countries in the world and its Casa de Grimaldi is one of its richest families in history. It is distantly related to other prominent European families such as House of Baden, House of Lorrach, House of Württemberg, House of Hanover, Polignac, Ducal House of Hamilton, House of Urach, House of Métrode-Westerloo, House of Bavaria and House of Oldenburg. The Kong family tree or descendants of Confucius have been documented as having one of the best family trees in history. While some families may trace their lineage further back than this one does, it still stands out as having one with an impressive amount of detail. These families have been included on this list due to their deep belief that they truly descended from these legendary figures. While ordinary people can keep track of their family trees for fun or curiosity's sake, royal families need to prove their lineage and their right to rule.