Private letters written by Pope Francis to a papal envoy over the use of condoms in aid missions to Africa to prevent sexually transmitted diseases have been published online.

A medieval order called the Knights of Malta, founded in the 11th century during the crusades, supported handing out prophylactics to help stop the spread of HIV-AIDS.

This was directly in contravention of the Catholic church's teachings on contraception.

Prince and Grand Master of the Order, Matthew Festing, was adamant that Grand Chancellor, Albrecht Freiherr von Boeselager, should be held responsible and dismissed him in January 2017.

Von Boeselager, who served as health minister for the Order, was said to have approved funds for the aid mission in Africa that distributed condoms.

He appealed to Pope Francis, who has supported the use of contraception for disease prevention in the past, such as the Zika virus.

Pope Francis meeting with Briton Matthew Festing (left), Prince and Grand Master of the Sovereign Order of Malta during a private audience at the Vatican in 2016

Wikileaks founder Julian Assange has been has been holed up in the Ecuadorian embassy since 2012

His predecessor, Benedict XVI, had argued it was morally licit for a male prostitute with HIV-AIDS to use a condom.

Pope Francis appointed a papal commission to investigate the Order and von Boeselager was reinstated at the same time as Festing was ousted.

Von Boeselager was adamant he did not know the condom distribution was taking place and took action to stop it when he found out.

The unprecedented and public dispute between the Vatican and the Knights was seen by Holy See watchers as a proxy war between Church liberals and conservatives, led by American cardinal Raymond Burke.

The Pope wrote in his letter to Cardinal Raymond Burke: 'I would be very disappointed if ‒ as you told me ‒ some of the high Officers were aware of practices such as the distribution of any type of contraceptive and have not yet intervened to end such things.'

The pontiff's intervention was seen by his critics as undermining the Knights of Malta's sovereignty and independence.

Pope Francis convened a five-strong team to investigate the Knights of Malta over their support for condom distribution in aid missions in Africa

His letter, which was published by WikiLeaks yesterday, shows the Pope was aware of and involved in the dispute since at least November 2016 when he met with the traditionalist Cardinal Burke.

The Pope also wrote: 'I have no doubts that by following the principle of Paul and speaking the truth in love, the matter can be discussed with the Officers and the necessary rectification obtained.'

WikiLeak's intervention into Vatican business has concerned Catholics that further more sensitive documents might be released at a later date.

Marco Politi, a veteran Vatican writer told the Washington Post: 'The fact itself, Wikileaks entering the internal affairs of the Vatican, is an alarm bell... Will there be a subsequent Wikileaks [release] on something not previously revealed? Should Wikileaks pull out stuff regarding paedophilia or banking scandals, then we would be onto something new.'

Grand Master of the Knights of Malta Matthew Festing waits for the start of a Mass at the Vatican in 2017

Conservatives say any use of condoms violates Church teaching that considers all forms of contraception to be an unacceptable barrier to life.

The Knights, a Church-linked charity body descended from the crusaders of the Middle Ages, refused to co-operate with the papal commission.

Burke is a prominent conservative figure who has been outspoken in his criticism of Francis's efforts to reform Church teaching on questions related to the family, marriage and divorce.

The Order of Malta was founded in Jerusalem in 1048 as a community of hospitals caring for the sick.

It was recognised by the pope in 1113, and now operates in 120 countries, managing hospitals and clinics, with 13,500 members and 100,000 employees and volunteers.