Do you think your family originated from the top 1 percent?

According to a new study of unique last names from around the world, moving in or out of the upper class doesn’t take just a few generations — it takes centuries.

Measuring not just income and wealth but also occupation, education, and longevity, researchers found that upper-class families took 300 to 450 years before their scions fell back into the middle class. Throughout society, poor families, taken as a whole, took an equal amount of time — 10 to 15 generations — to work their way up into the middle class.

Researchers at the University of California, Davis, and the London School of Economics conducted the study, which they published in the journal “Human Nature.” The researchers based their study on families with unique last names. Those unique last names made it possible to trace the families through genealogical and other public records. In England, those aristocratic names included Atthill, Bunduck, Balfour, Bramston, Cheslyn, and Conyngham.

Enter your last name to learn its meaning and historical family occupation.

The social scientists looked for those and other unique, upper-class surnames among students who attended Oxford and Cambridge universities between 1170 and 2012, rich property owners between 1236 and 1299, as well as probate records since 1858 — which are available on Ancestry.

They found that social mobility in late medieval England wasn’t any worse than in modern England. Illiterate village artisans in 1300 took seven generations to incorporate fully into the educated elite of 1500. Conversely, if you died between 1999 and 2012 and had one of the 181 rare surnames of wealthy families in the mid-19th century, you were more than three times as wealthy as the average person.

The glacial pace of overall social mobility appears to be a universal phenomenon, no matter the political forces at work. Researchers found 13 unusual Chinese surnames among the educated elite in the 19th century. Today, despite the Chinese Communist revolution, social upheavals of the Cultural Revolution, and exile of many families to Taiwan and Hong Kong, holders of the 13 surnames are still disproportionately affluent and influential as professors and students at elite universities, government officials, and heads of corporate boards.

Researchers aren’t sure why social mobility appears to move so slowly, despite outside political and social forces, and suspect genetics may play a role.

The United States isn’t even old enough yet to test the researchers’ theory. But that hasn’t stopped many observers from identifying certain surnames that connote wealth in the United States.

There are, for example, about 100 Mellons alive today sharing $12 billion, the fruit of a bank their forefather Andrew W. Mellon founded in the mid-1800s. The several hundred living members of the Rockefellers share $10 billion in wealth that started when John D. Rockefeller founded Standard Oil in 1870.

With just $1 billion, the Kennedy family’s wealth is eclipsed by the assets of less romantic family dynasties (the wealthiest family in the world, the Waltons, trace their riches to the founding of Wal-Mart in 1962), but the 30 Kennedy heirs live with a name associated with America’s Camelot.

Time will tell how long it takes those heirs to end up driving a cab. In the meantime, if you have a unique surname, or even if your last name is Smith, Ancestry can help you find out where your ancestors worked, how well they were educated, and how long they lived — all signs, according to researchers, of their place in the social hierarchy.

Discover your own family’s upward (or downward) mobility. Start a free trial.