Former Alaska Gov. Sarah Palin's husband Todd Palin has filed for divorce in Anchorage Superior Court.

Citing "incompatibility of temperament between the parties such that they find it impossible to live together as husband and wife," the court document, filed on Friday, uses initials instead of full names, but lists the date of the Palin marriage in August 1988 and the birth date of their child, Trig, 11, who has Down Syndrome and for whom they filed joint custody.

Anchorage attorney Kimberloo Colbo is representing Todd, 55, and has asked the court to keep the case confidential. As well as Trig, the couple has four adult children, Track, 30, Bristol, 28, Willow, 25, and Piper, 18.

Sarah Palin, also 55, rose to prominence during the 2008 presidential election, when the former mayor of Wasilla was chosen by John McCain as his vice presidential candidate, a decision for which the Arizona senator expressed regret last year. The photogenic couple - he was known in Alaska as the "First Dude" and was a champion snowmobile racer - were an immediate media sensation.

She was first elected as Alaska governor in 2006 and resigned in 2009. She later became a populist voice in the Republican Party, a prominent figure in the rise of the Tea Party and was one of the first to endorse President Trump when he was a candidate.

There have long been rumors of a Palin divorce. A decade ago, People magazine reported alleged “extramarital affairs on both sides and an impending divorce" and claims that she was planning a move to Montana. A “Palin rep” responded at the time: “No truth to any of the rumors. No divorce. No affairs. No land in Montana. Nothing! All lies and fabrications!” Sarah Palin posted on her Facebook page that “yet again, some so-called journalists have decided to make up a story."

The Palin family has been no stranger to turmoil. Though she publicly promoted abstinence before marriage, Bristol became pregnant by her boyfriend, Levi Johnston, 29, while a teenager, which became a source of controversy during the 2008 campaign. The two later ended their relationship and have since had public feuds. The former Alaska governor herself slammed Johnston when he posed suggestively for Playgirl in 2009.

Bristol and her husband, Medal of Honor recipient Dakota Meyer, 31, divorced in 2018 following an acrimonious marriage, though the couple have since reportedly patched things up.

Their oldest son, Track, has faced legal troubles, perhaps most notably when he was arrested on assault and burglary charges in 2016 after breaking into his parents' home and attacking his father about a truck. He has been arrested on violence-related charges multiple times since then.