Every year, the Social Security Administration releases a list of the top baby names from the previous year, providing parents-to-be with a little inspiration and perhaps a fair warning, for those who hope to go off-trend with a less common name. At a minimum, the SSA list offers a tantalizing window into the naming game itself, a game that’s as old as time! Perusing the data, one is struck most by the extent to which naming trends wax and wane — while some baby names have decades worth of staying power, others fall out of favor fast.

These days, Olivia’s and Liam’s are everywhere, but those names were barely on the radar 20 years ago (when they would’ve most likely been named Emily and Jacob). And when you look back even further — say, to 1972 — you realize they would have been named Jennifer and Michael. But how is one popular baby name iconically of its time, and another isn’t?

While that’s a mystery science has yet to fully illuminate, we can look back across the decades and find unmistakable patterns, as Jennifer’s lose ground to Ashley’s and Emily’s cede to Sophia’s, before becoming Olivia’s.

Fifty years ago, Noah and Emma would’ve been named Michael and Jennifer, or Christopher and Michelle — textbook Gen X names — and the millennial brothers and sisters from 1982 that they practically raised were almost assuredly going to be some combination of Christopher David and Jessica Nicole. Of course, they’re all now your next-door neighbors, whose own tween children are likely named Jacob and Sophia or Ava and Mason.

Ava, which was the fifth most popular name in 2012, wasn’t even on the map before the late aughts — and she would’ve been Alexis in 2002, Sarah in 1992, Melissa in 1982, and Amy in 1972. Meanwhile, her 10-year-old brother, Mason, which was the second-most-popular boy’s name in 2012, would’ve been Michael in 2002 or Christopher in 1972, ’82, or ’92.

One lesson? Everything old will be new again, and we might expect a resurgence of Christina’s and Kimberly’s and Brian’s and Robert’s in the next couple of decades, as Gen Z starts naming their babies after Gen X grands and great-grands. Bell bottoms are back again for the second time in 50 years, so surely we can expect a bumper crop of baby Lisa’s any day now. And old-fashioned names are super hot at the moment: Evelyn, Benjamin, and Henry used to be your great-grandparents, but today they’re taking their first steps and starting daycare.

Without further delay, here’s a journey through the past half-century of the naming game — from the nearly extinct to the tenaciously popular, there’s inspiration everywhere.