In the early hours of Wednesday, Zimbabwe’s army went on the air to announce that they had taken control. This had become increasingly clear, as armoured personnel carriers and troops had been seen around Harare on Tuesday and the state broadcaster – ZBC – had been surrounded.

The statement read out by Major General S.B. Moyo couched their actions as an attempt to uphold the existing order.

“We are only targeting criminals around him who are committing crimes that are causing social and economic suffering in the country in order to bring them to justice. As soon as we have accomplished our mission we expect that the situation will return to normalcy.”

But no-one was under any illusion about what was taking place: this was a coup by another name. Nothing like it had been seen in Zimbabwe since Mugabe took power in 1980.

The war veterans, who had stood by President Mugabe during all the crises and challenges he had faced, were not prepared to see Grace and her acolytes to take control.

Since her marriage to the president in 1996, the First Lady of Zimbabwe has become legendary for her ostentatious living. While her countrymen and women live on the breadline, “Gucci Grace”, or “the first shopper” as she is known, indulged her lavish lifestyle. The Mugabe family accumulated a substantial property portfolio both inside Zimbabwe and abroad.

Notorious for her vicious temper, Grace was only recently smuggled out of South Africa after escaping an assault charge for hitting a model.

Zimbabweans complained, but it was when Grace began to seek political office that she crossed a line. She began to be hailed as party rallies as the “Mother of the Nation”. Grace surrounded herself with her acolytes: Generation 40, or G40, faction which included the ZANU PF youth wing. She began pushing her husband to nominate her his successor.

This brought her up against the old guard, who coalesced around the vice president, Emmerson Mnangagwa. Last week Mnangagwa was sacked and he fled to South Africa via Mozambique. It was this that triggered the current events.

By dismissing Mnangagwa, Mugabe had broken with someone who had stood by him since the earliest days of the war against Ian Smith and white rule. Mnangagwa had led the first group of guerrillas to China for military training. After finishing his training, Mnangagwa returned to Tanzania in May 1964, where he and other returning ZANU guerrillas formed the “Crocodile Gang”.

Mnangagwa was captured after blowing up a railway train in Rhodesia, and only narrowly escaped the death sentence. He spent 10 years in jail and was released in 1974 as part of the “unity talks” amnesty. In Mozambique, he was elected special assistant to the president at the 1977 Chimoio congress – which meant he was the military and civilian representative of the party. He also accompanied Mugabe to the Lancaster House negotiations, which paved the way for official recognition of the state of Zimbabwe.

After independence Mnangagwa stood by Mugabe, and was responsible for the suppression of the Ndebele, as well as involved in the rigging of elections. He held a string of ministries, including – importantly – Defence from 2009 to 2013.

It was precisely because he represented such a threat to Grace’s succession that Mugabe removed Mnangagwa from the vice presidency. He was accused of displaying “traits of disloyalty, disrespect, deceitfulness and unreliability”.

The scene was set for the current showdown. On Monday the army chief of staff, General Constantino Chiwenga, warned the president to “stop” purges by the ruling ZANU-PF party. “We must remind those behind the current treacherous shenanigans that when it comes to matters of protecting our revolution, the military will not hesitate to step in,” he said at a press conference.

ZANU PF responded on Tuesday by issuing a statement accusing General Chiwenga of treason. The party said the general’s comments were “calculated to disturb national peace… [and] incite insurrection”. Since treason is a capital offence in Zimbabwe, the general was left with few options: fight or flee the country. He – and most of the military – chose the former.

What lies ahead? It is possible that Mugabe will be allowed to retire and live with some dignity. There are suggestions he might be allowed to leave the country for Singapore or Malaysia, to enjoy the wealth he has salted away overseas for many years. But Mugabe in exile might be unpalatable to the military, since he could act as a magnate for dissidents.

There are reports that Mnangagwa has returned to Zimbabwe and – together with General Chiwenga – will act to shore up his position, while proclaiming that they are acting to “protect the revolution”.

At present South Africa – a critical player during the Rhodesia crisis, and still the major power in the region – is attempting to keep its distance. Speaking on Tuesday ANC secretary-general Gwede Mantashe made it clear that the ANC doesn’t want to get involved in the rift. “ZANU-PF must deal with that issue because Zimbabwe is not our colony… it’s not our province, it’s our neighbour. If things go wrong there, of course, we’ll be concerned because it’ll impact on us, but we have no authority over them, that’s the point we’re making.”

How long Pretoria can keep a cool detachment will depend on whether the factions within Zimbabwe can find an orderly way of resolving the current crisis.