The legacy of North Africa's past monarchies
Looking into the history of monarchy in North Africa, I discovered that modern Tunisia has had one king, who lasted just over one year and was called, surreally given the flash in the pan nature of this reign, King Mohammad VII.
His tale and that of other monarchies in North Africa highlights why succession is such a problem.
For centuries, the Ottoman Empire ran the North African littoral through princelings known by various titles such as the Bey of Tunis or the Khedive of Egypt.
Almost all were pashas or generals and assumed the character of enforcers, collecting taxes and running affairs in return for a chance to milk their opportunity for riches.
Since the hereditary principle had been abandoned by the Ottoman sultans (who felt that a man expecting his own son to take over might violate the will of God) their formula produced a situation that is all too familiar to many Arabs - constant intrigue, venality, power resting on armed force, and, most relevant in the light of events in Tunis, a complete uncertainty over who should take over when the old ruler disappeared.
This imperial legacy has produced one positive effect - stability in power.
Libya's leader has been at the helm since 1969 and Egypt's strongman for 30 years. Morocco, which boasts the region's last surviving monarch, has a king who has been on the throne for 11 years.
Mohammad VII of Tunisia was installed as bey by the French and then became king when the country declared independence in 1956.
Lacking the necessary support of the country's elite, he was elbowed aside by Habib Bourguiba whose strength in the independence movement and on the streets gave him the necessary clout to rule.
Mr Bourguiba was himself pushed out in 1987 by his prime minister, Zine al-Abidine Ben Ali.
The fate of these leaders gives some idea why many Tunisians were suspicious when the current prime minister declared himself "acting president" on Friday night.
He has since been superseded by the parliamentary speaker.
So far, it would appear that the key to exercising authority in Tunisia today is the support of the army. It retains greater public respect than the police or security service, both of which were seen as tools of Mr Ben Ali's repression.
Human rights groups have condemned the interim government announced today as a collection of Ben Ali placemen (including in the key security positions) with a sprinkling of opposition politicians in minor posts.
It is clear then both that nobody knows yet who will succeed Mr Ben Ali or whether the leader eventually appointed will come to power by ballot or by the ability to rally the forces necessary to suppress disorder on the streets.
And that is a reality that would have been all too familiar to the ineffectual King Mohammad VII.