Brotherly love turned to conflict and estrangement is not an uncommon story in families. That's why so many people are fascinated with the British Royal Family and the current meltdown between Princes Harry and William.
We want to know what happened. They seemed bonded in the dark days after their mother Princess Diana's untimely death and funeral in 1997.
Would grief not strengthen the ties that bind? Surely they would be inextricably bound for the rest of their lives after the traumatic loss of their beloved mother.
Yet when you consider the patriarchy, racism, misogyny and colonialism so deeply embedded in the British monarchy, their estrangement starts to make sense.
The ties that bind - or divide
But first, what do we know about sibling relationships? They are not well studied but we do know that these relationships can be sources of both risk and resilience.
Studies show that dysfunctional sibling relationships can result in concerning mental health outcomes - anxiety, depression and substance abuse. Or conversely, they can be great sources of support in healthy psycho-social development, providing strength in the face of adversity.
Siblings can also experience both types of relationships at different times. Even when sibling relationships are fraught with conflict, the very same siblings can display fierce loyalty to each other when criticized or attacked.
Next we need to bring in larger family dynamics and something called family systems theory - the idea that the whole is more powerful than the sum of its parts. Part of this rests on the notion that a deeper examination of what we see on the surface of families reveals what lies beneath.
External forces also operate in the larger ecology of families that play out in everyday life. Knowing the values and belief systems of families, including their cultural influences, helps us understand what bubbles up to the surface of sibling relationships. This seems particularly pertinent to the Harry and William situation.
Scapegoating a family member
To better understand their relationship, it's also helpful to know about triangles.
That means when two family members join forces against one, resulting in scapegoating. In his record-breaking memoir, Spare, Harry alleges that King Charles and Prince William have been doing this to him for many years.
Families employ scapegoating when they want to blame a family member for problems or use them to deflect from larger, more entrenched issues. Harry is seemingly the Royal Family's scapegoat for other, more significant problems.
Let's start with his uncle, Prince Andrew, who had an association with sex trafficker Jeffrey Epstein and has allegedly sexually abused an underaged girl. The Royal Family paid Pound 12 million, almost $20 million, to settle a lawsuit with one of his accusers.
Andrew, an accused sex offender, was purportedly Queen Elizabeth's favourite child, and he's polling higher than Harry and Meghan in surveys of older British people.
Fairness and favouritism are also known to undermine sibling relationships. Obviously, the monarchy is literally based on the institutionalized favouritism of lineage. The crown is passed on by birth order and until recently, gender.
The impact of birth order
Birth order is another determining factor in how siblings will or will not get along. William will be king and Harry is now further down the line of succession, and is no longer "the spare," as he was callously declared by his father upon his birth.
Spares and women are considered "lesser than" in this patriarchal, colonial system - backups just in case something should happen to the heir. Thankfully, this age-old tradition has changed recently - Prince William's daughter, Charlotte, will remain behind her older brother George but ahead of her brother, Louis, in the line of succession.
Family systems theory further argues that without intervention, patterns repeat over generations. The Royal Family seems to epitomize this inter-generational repetition of dysfunctional patterns.
Harry's situation, for example, is similar to his great Uncle Edward's break from the monarchy when he abdicated the throne to marry American Wallis Simpson decades ago.
Adjectives used to describe Simpson, then and now, drip with misogyny and disdain, including derogatory remarks about her alleged eating disorder (like Diana's struggles), drinking and divorce status. It seems Harry's wife is a similar target as she's been bombarded for years with sometimes openly racist remarks and described as difficult and abrasive by William, according to Harry.
Harry takes the heat
Exiting the Royal Family has come with grave consequences for Harry and Meghan, including being cut off from security despite the relentless and often incendiary attacks against them by the British media.
British subjects seem to consider their departure, along with Harry's memoir, as the ultimate betrayal. The British media is currently fixated on Harry and Meghan - not Andrew, and the allegations of sex crimes against him, and not the monarchy itself, its enduring colonial attitudes and the fact that several Commonwealth countries want to cut ties.
Scapegoats take the heat for a family's sins and help keep those sins hidden, especially in high-profile families. "Never complain, never explain" is the Royal Family motto, although Harry alleges his relatives indulge in both regularly by leaking and planting stories about other family members to avoid negative media coverage.
Harry has disrupted these tactics, however, by exposing them. His ordeal has also reminded the world of the racism running through the colonial veins of the British monarchy and its involvement in the enslavement of Africans and the transatlantic slave trade.
The racist attacks on Meghan was Harry's main stated reason for fleeing - and to protect his wife and their children from the dangers posed to them in the United Kingdom.
So what will happen with King Charles's coronation in May? My guess is that an olive branch will be offered to Harry and Meghan, with invitations extended to them, and there may even be some internal pressure to bring them back into the fold.
But if the old family patterns inextricably tied to patriarchy, racism, misogyny and colonialism persist, Harry will almost certainly resist that pressure - and the monarchy will also be forced to either totally reinvent itself or risk being abolished in the years to come.
In other words, this is one sibling feud that could have historical repercussions.
Author: Ramona Alaggia - Professor, Social Work, University of Toronto