Keep your eye on that grandfather clock — the 15th anniversary of Downton Abbey is nearly here. The franchise hits that milestone on September 26, two weeks after the September 12 release of its third and final film, Downton Abbey: The Grand Finale.

PBS’s Masterpiece anthology opened the Abbey’s doors for us in 2010, and since then, we’ve seen the members of the aristocratic Crawley family and its staff progress through the early 20th century — getting older, growing up, starting families, starting new careers, enjoying joyous highs, and enduring devastating lows, all while calamitous world events threatened their livelihoods.

Don’t forget: It was the sinking of the Titanic that thwarted the plan to marry Lady Mary (Michelle Dockery) off to her second cousin, Patrick, to keep the Crawleys’ fortune with the immediate kin. The family learns in Downton’s series premiere that Patrick was aboard that doomed ocean liner, and the next heir in line is a handsome unknown named Matthew Crawley (Dan Stevens)…

So began many onscreen trials and tribulations for the Crawleys and their servants. Here’s how we’d rank the seasons that ensued.