Jordan's King Abdullah has stripped his half-brother Hamzah of the title of crown prince, overriding the dying wish of their late father King Hussein.
Crown Prince Hamzah was married last year
Prince Hamzah, 24, was relieved of his "symbolic" duties in a letter from the monarch on Sunday.
It would "allow you more freedom to work in any tasks I assign to you", the king's letter said.
Analysts say it shows how the king's command has grown since coming to power in 1999 without political experience.
In a letter to the king released by the state news agency, Petra, the former crown prince said he accepted his brother's decision.
He said he would stand by King Abdullah "as a faithful soldier and a devoted supporter... out of my loyalty, love and obedience".
Prince Hamzah was a favourite of Jordan's previous monarch, King Hussein, who often described him in public as the "delight of my eye".
However, he was seen as too young and inexperienced to be named successor, when the dying king dismissed his brother Hassan as crown prince in favour of his son, Abdullah.
The latest move is seen a blow to King Hussein's favourite wife, Hamzah's mother Queen Noor.
Correspondents say her plans for Hamzah to succeed Hussein were derailed by her husband's premature death from cancer - but as long as he was crown prince her hopes were not completely extinguished.
The position of crown prince is being kept vacant - but analysts say King Abdullah is expected to appoint his own son, Hussein, now aged 10, at some point in the future.
'Soldier of the nation'
King Abdullah's letter, which was read out on Jordanian TV, described Hamzah as a "sincere soldier of this nation".
The king said the title of crown prince was an "honorary position, which does not give authority for its holder nor does it give him any responsibility".
"That had prevented me from assigning you certain responsibilities."
He said this would make it possible for Prince Hamzah "to take up other posts, something which was not possible as crown prince".
A graduate of the UK's Royal Military Academy, Sandhurst, Prince Hamzah is a captain in the Jordanian armed forces.
Government sources said that Sunday's shake-up came after consultations between the king and his brothers - although it is not clear if Prince Hamzah was included.
Correspondents say there has never been any visible rivalry between Abdullah and Hamzah.
The king hosted a gala reception for him in May 27, when the royal family officially celebrated the prince's marriage.
Despite being the eldest son, career soldier Abdullah - who is half-English and married to a Palestinian wife - was never seen as Hussein's probable successor.
But his reputation as a politician has grown since taking over Jordan's absolute monarchy five years ago.