What is the most number of times someone has become leader of a European country?

Erik of Pommerania, King of Sweden-Finland, elected king of Sweden three times (while being King of Denmark and Norway continuously for 43 and 52 years.

Karl Knutsson Bonde, riksföreståndare one time, and elected king three times (so practically king 4 times.)

The situation was mainly caused by the Swedish nobility using the strains on the swedish population due to Erik's war with Hansan as a way to weaken the king's ability to rule in his own power.

I've an alternative with six separate ruling periods (but seven cabinets): Antonio Cánovas del Castillo, first the President of the Ministry of the Regency and later the President of the Council of Ministers of Spain:

• 31-Dec-1874 to 12-Sep-1875 (President of the Ministry of the Regency);
• 02-Dec-1875 to 07-Mar-1879 (henceforth, the President of the Council of Ministers);
• 09-Dec-1879 to 08-Feb-1881;
• 18-Jan-1884 to 27-Nov-1885;
• 05-Jul-1890 to 23-Nov-1891 and after a cabinet reshuffle from 23-Nov-1891 to 11-Dec-1892;
• 23-Mar-1895 to 08-Aug-1897 when he was assassinated.

Cánovas del Castillo was President for seven cabinets (i.e., governments) though as noted above one of these continued on from his own prior rule.

Cánovas del Castillo is actually surpassed in the number of cabinets by Práxedes Mateo Sagasta who led twelve cabinets, but who was President for only 'five' separate occasions, the others representing reshuffles.

This was the intended way for the Spanish government to rotate in their 'peaceful turn'.

Does Republican Rome count? The Consuls (who were normally elected in pairs) alternated months of primacy so, arguably, each had six one-month periods of leadership. And many men were elected to more than one consulship, typically a decade or so apart giving them a dozen.

Among the equivalents of prime ministers, Mehmed Said Pasha (1830-1914) was Grand Vizier of the Ottoman Empire eight times: 1879-1880, 1880-82, 1882, 1882-85, 1895, 1901-03, 1908, and 1911-12. He was fortunate that it was no longer common to execute grand viziers when they lost their office, especially since during most of his times in office he would have been too old and unfit to win a race for his life with the executioner as was the custom.

https://en.wikipedia.org/wiki/Mehmed_Said_Pasha1

Among true European prime ministers, the answer of Pieter Geerkens states that Aristide Briand became Prime Minister of France eleven times in six non contiguous time periods. According to Wikipedia's article on him he had six periods of power.

First period includes first and second Briand governments 1909-1911, 2nd period and 3rd & 4th Briand governments in 1913, 3rd period and 5th & 6th Briand governments 1915-1917, 4th period and 7th Briand government 1921-1922, 5th period and 8th, 9th, and 10th Briand governments 1925-26, 6th period & 11th Briand governments 1929.

https://en.wikipedia.org/wiki/Aristide_Briand2

Person who became monarchs the most times in Europe - several different possible record holders depending on various criteria:

1) Possible record holder: Rurik I or II Rostislavich, grand prince of Kiev five, six, or seven times?

As OON said in his answer, Rurik Rostislavich became grand Prince of Kiev seven times: 1173, 1180, 1194-1202, 1203-04, 1205-06, 1206-07, and 1207-1210.

Or did he? Wikipidia lists only 6 reigns: 1173, 1180-82, 1194-1202, 1203-05, 1206, 1207-10.

https://en.wikipedia.org/wiki/Rurik_Rostislavich3

Wikipedia's list of rulers of Kiev lists five reigns: 1173, 1180-82, 1194-1202, 1203-06, and 1207-10.

https://en.wikipedia.org/wiki/Grand_Prince_of_Kiev4

Regnal Chronologies lists the following six reigns: 1172, 1180-1202, 1203, 1205-1206, 1206-08, and 1208-11.

http://my.raex.com/~obsidian/ukraine.html#Kiev5

According to Medieval Lands, Rurik was Grand Prince of Kiev five times: 1194-99, 1203, 1205-06, 1206-1207, and 1207-1211. And possibly was a co-grand prince earlier.

http://fmg.ac/Projects/MedLands/RUSSIA,%20Rurik.htm#RiurikIIRostislavichdied1215A6

So with all the different dates for when Rurik I or II Rostislavich gained and lost the title of Grand Prince of Kiev, I don't know if he was Grand Prince five, six, seven, or even more times.

2) Possible record holder: Constantine Mavrocordatos, became Prince of Wallachia or Prince of Moldavia ten times. But he was an ottoman vassal ruler.

Constantine Mavrocordatos (1711-1769) was the vassal Prince of Wallachia six times: 1730, 1731-33, 1735-1741, 1744-48, 1759-1758, and 1761-63, and the vassal Prince of Moldavia four times: 1733-35, 1741-43, 1748-49, and in 1769.

https://en.wikipedia.org/wiki/Constantine_Mavrocordatos7

3) Possible tied record holders: Dan II (d. 1432) and Basarab II, Princes of Wallachia five times each. They were more independent than Constantine mavrocordatos, but were still sometimes vassals or tributaries of the Ottoman Sultan and/or the King of Hungary.

Dan II (died 1432), son of Dan I, was Prince of Wallachia in 1420-21, 1421-23, 1423-24, 1426-27, and 1427-1431.

https://en.wikipedia.org/wiki/Dan_II_of_Wallachia8

Basarab III (died 1480), son of Dan II, was Prince of Wallachia in 1473, 1474, again later in 1474, 1475-75, and 1476-1477.

https://en.wikipedia.org/wiki/Basarab_Laiot%C4%83_cel_B%C4%83tr%C3%A2n9

Who was ruler of the Roman Republic or Empire the most times?

The Roman consuls were heads of state and heads of government of the Roman Republic. Consuls were almost always elected two at a time for one year periods. The Roman emperors became more or less elective, hereditary, and/or usurpative (if that is a word) political bosses of the Roman republic, being at first the power behind the republic and gradually becoming more and more the openly monarchial leaders of the Roman state over centuries. During the Empire emperors began to appoint the consuls.

1) Gaius Marius (147-86 BC) was elected Roman consul seven times, which was unprecedented during his lifetime.

But his consulships were in only three nonconsecutive periods of time:

First Period and 1st consulship 107 BC, with Lucius Cassius Longinus; second period and 2nd, 3rd, 4th, 5th, and 6th consulships 104 to 100 BC, with Gaius Flavius Finbria, Lucius Aurelius Orestes, Quintus Lutatius Catalus, Manlius Aquillius, and Lucius Valerius Flaccus; and third period and 7th consulship 85 BC with Lucius cornelius Cinna.

Other Romans were consuls in three or more non consecutive periods during the Republican era.

2) Titus Quinctius Capitolinus Barbatus, consul six non consecutive times. First period & consulship 471 BC, with Appius Claudius Sabinus; 2nd consulship 468 BC, with Quintus Servilius Priscus Structus; 3rd consulship 465 BC with Quintus Fabius Vibulanus; 4th consulship 446 BC, with Agrippa Furius Fusus; 5th consulship 443 BC, with Marcus Greganius Macerinus; and sixth period and consulship 439 BC,with Agrippa Menenius Lanatus.

https://en.wikipedia.org/wiki/Titus_Quinctius_Capitolinus_Barbatus10

3) A somewhat later and more historically certain six time consul was Marcus Valerius Corvus, (c.370 to c. 270 BC), But his last 2 consulships were consecutive in 300 and 299 BC, which gives him only 5 nonconsecutive periods of office as consul. he was also chosen as dictator twice, but his terms as dictator were consecutive with some of his terms as consul, so he was ruler in only 5 nonconsecutive periods.

https://en.wikipedia.org/wiki/Marcus_Valerius_Corvus11

The consuls were replaced from 444 BC and from 408 to 394 BC and from 391 to 367 BC by three to ten consular tribunes or tribuni militum consulari potestate, "military tribunes with consular power" each year.

4) Lucius Furius Medullinus (c.445-c.375 BC) was consular tribune seven times and consul two times, with seven nonconsecutive periods in shared power.

He was consul in 413 BC with Aulus Cornelius Cossus and in 409 BC with Gnaeus Cornelius Cossus, and consular tribune in 407 BC with 3 colleagues, in 405 BC with 5 colleagues, in 398 BC with 5 colleagues, in 397 BC with 5 colleagues, in 395 BC with 5 colleagues, in 394 BC with 5 colleagues, and in 391 BC with 5 colleagues. So his nine terms as consul or consular tribune give him seven nonconsecutive terms as the ruler (with colleagues) of Rome.

5) In imperial times Flavius Aetius (391-454) was the person unrelated to the imperial family who became consul the most, being consul three times, in 423, 437, and 446; the Flavius Aetius who was consul in 454 apparently being someone else. At that time the consulship was merely an honor.

https://en.wikipedia.org/wiki/List_of_Roman_consuls12

https://en.wikipedia.org/wiki/Flavius_Aetius13

6) The emperor who became consul the most times was apparently the eastern Roman emperor Flavius Theodosius Junior II the Younger (401-450) who was consul eighteen times: in 403 (West), 407 (W), 409 (W), 411 (W), 412 (W), 415 (W), 416 (W), 418 (W), 420 (W), 422 (W), 425 (W), 426 (W), 430 (W), 433 (W), 435 (W), 438 (W), 439 (W), and 444 (W). Of course his power did not come from being consul.

https://en.wikipedia.org/wiki/List_of_Roman_consuls12

https://en.wikipedia.org/wiki/Theodosius_II14

7) Marcus Aurelius Valerius Maximianus Herculius Augustus (c. 250-310) was appointed Caesar or junior co emperor by Diocletian in 285 and Augustus or senior co emperor in 286. He abdicated and retired with Diocletian in 305 but in 306 proclaimed himself Augustus again. In November 308 a conference of emperors and would-be emperors met and Maximian was forced to abdicate again. Maximian proclaimed himself Augustus again in 310 but was defeated by Constantine and killed himself. Thus Maximian Can be counted as a three time Roman emperor and/or Roman usurper.

8) Eastern emperor Zeno (c.425-491) reigned from February 474 to January 475, was deposed by Basilicus, and regained the throne in August 476. Emperor Justinian II (668/9-711) reigned from 685 to 695, and again from 705 to 711. Thus they are tied for reigning twice.

Romanian rulers with multiple reigns:

As most people know, Vlad II or III Dracula or Tepes (1428/31-1476/77) was Prince of Wallachia three times, in 1448, from 1456-62, and in 1476. But other Romanian rulers had more reigns than that:

In Wallachia Radu III "The Fair" ruled 4 times between 1462-1475 and Radu V ruled four times from 1522-1529. Dan II (died 1432) ruled Wallachia five times: 1420-21, 1421-23, 1423-24, 1426-27, and 1427-1431; and Basarab III "the Old" ruled Wallachia five times: 1473, 1474, 1474, 1475-76, and 1476-77.

Grigore II Ghica became the vassal Prince of Moldavia four times: 1726-33, 1735-39, 1739-41, and 1747-48, and the vassal Prince of Wallachia two times: 1733-35 and 1748-52.

https://en.wikipedia.org/wiki/Grigore_II_Ghica15

Constantine Mavrocordatos (1711-1769) was the vassal Prince of Wallachia six times: 1730, 1731-33, 1735-1741, 1744-48, 1759-1758, and 1761-63, and the vassal Prince of Moldavia four times: 1733-35, 1741-43, 1748-49, and in 1769.

https://en.wikipedia.org/wiki/Constantine_Mavrocordatos7

Michael I (1921-2017) was king of Rumania twice, from 1927 to 1930, and from 1940 to 1947.

Monarchs of England with multiple reigns:

Aethelred the Unready (c.966-1016) reigned twice: 978-1013, and 1014-1016; Henry VI (1421-1471) reigned twice: 1422-1461 and 1470-1471; and Edward IV (1442-1483) reigned twice: 1460-1470 and 1471-1483.

Monarchs of Scotland with multiple reigns:

Edward balliol (c.1283-1367) was briefly king in parts of Scotland three times: in 1332, 1333-1334, and 1335-1336; and Charles II was king twice: in 1649-1652 and 1660 to 1685.

Irish monarchs with multiple reigns:

Mael Sechnail II Mor mac Domnail (949-1022) was high king of Ireland twice, from 980 to 1002 and from 1014 to 1022, as well as being King of Mide 976-1022.

Welsh or Brythonic monarchs with multiple reigns:

Gruffudd ap Cynan (c. 1055-1137) was King of Gwynedd four times: in 1075, 1081, 1097?-1098, and 1099-1137. He might have also claimed to be King of the Britons and possibly claimed to have been a Roman emperor in succession to Constantine III.

https://en.wikipedia.org/wiki/Gruffudd_ap_Cynan 16

According to Gildas in The Ruin of Britain, Maglocunnus, the Dragon of the Island, ruled an unspecified kingdom (or multiple kingdoms) twice.

Monarchs of France with multiple reigns:

Napoleon I was emperor of the French twice: from 18 May 1804 to 4 April 1814 and from 20 March to 22 June 1815; His son Napoleon II (1811-1832) was emperor of the French twice: from 4 to 6 April 1814 and from 22 June to 7 July 1815; Louis XVIII was King of France twice: from 6 April 1814 to 20 March 1815 and from 8 July 1815 to 16 September 1824.

Spanish monarchs with multiple reigns:

Hisham II was Caliph of Cordoba from 976 to 1008 and from 1010-1012, while Sulayman II was caliph from 1009 to 1010 and from 1012 to 1016, and Al-Qasim ibn Hammud was Caliph from 1018 to 1021 and in 1023.

Bulgarian monarchs with multiple reigns:

Simeon II (born 1937) was King of Bulgaria from 1943 to 1946, and Prime Minister of Bulgaria from 2001 to 2005. He may have the record for the longest time between periods of power, 55 years.

Theophylactus of Tusculum (d. 1056) was "pope" - Bishop, Archbishop, Metropolitan, and Patriarch of Rome - and vassal ruler of the Papal States under the name of Benedict IX three times (1032-1044, 1045, and 1047-1048) despite allegedly being very evil and also being very young (allegedly 11 to 20) when he first became pope.

Ethiopia is in Africa but could be considered semi-European culturally. Tekle Giyorgis I (c. 1751-1817) was King of Kings six times between 20 July 1779 and June 1800.

Elizabeth II (born 1924) is a European monarch. During her lifetime she has become the monarch of about 32 different independent countries, and she is still the monarch of 16 them. But only the UK and Malta (1964-1974) are European countries.

Marcus Valerius Corvus was consul six times and dictator twice = total 8. He apparently lived to be around 100.

348 BC consul

346 BC consul

343 BC consul

342 BC dictator

335 BC consul

302 BC dictator

300 BC consul

299 BC suffect consul (he replaced another consul who had died so there was a gap between this one and the consulship in 300)

Titus Quinctius Capitolinus Barbatus was consul six times (471, 468, 465, 446, 443, 439 BC). He apparently died when he was 90 or more.

There's more info https://en.wikipedia.org/wiki/List_of_Roman_consuls and https://en.wikipedia.org/wiki/List_of_Roman_dictators#4th_century_BC

If you look to the medieval era I'm quite certain that you will find a lot of examples, however the problem will often arise that the definition of "the ruler of the country" may be debated. Some regions that were part of a larger country before or after were completely independent entities for centuries. On the other hand someone with a formal grandiose title could hold real power only over much smaller region.

Now, I'm not claiming that this will be a leader but still a rather bright example. Rurik Rostislavich (Рюрик Ростиславич) managed to become a Grand Prince of Kiev (Великий Князь Киевский) seven times.

To put some perspective this was a time when a formerly united Kievian Rus disintegrated into a bunch of independent principalities (that much later were gradually united by Moscow and Lithuania) ruled by the descendants of the one ruling family. Formally it was assumed that the prince that ruled over former capital Kiev was the most senior one having the most authority and a power to call and preside in the meetings of the princes. Because of his initial power and prestige he was called the Grand Prince of Kiev. However by the end of the 12th century the Grand Prince of Kiev had no actual power over other lands than the Principality of Kiev. In fact some powerful princes of the time didn´t try to hold this useless title and gave it to much weaker princes instead.

Still this didn't stop a lot of princes to try to become the Grand Prince of Kiev (especially because being from the one family each one of them could make up a claim that it was his right to rule) As result the title was getting from one prince to another often after only few weeks of rule. Rurik Rostislavich is a record-holder taking and losing this position seven times:

1. In 1173 he entered the city at night and managed to capture previous princes. After five weeks of rule he ran away to Belgorod when Andrey the Pious (Андрей Боголюбский) approached.

2. In 1180 he pushed a Grand Prince of Kiev Svyatoslav Vselodovich out of the city and claimed the title for himself. However very soon he had to give it back to Svyatoslav.

3. In 1194 Svyatoslav died and Rurik became a Grand Prince of Kiev. He managed to hold the title until 1202 when he was forced to give it away to Roman Mstislavich (also known as Roman the Great).
4. In 1203 he captured Kiev using his Cuman allies and won the title back again. However in 1204 he was captured, dethroned and tonsured by Roman Mstislavich. As result of the negotiations the son of Rurik became a Grand Prince of Kiev.
5. After the death of Roman Mstislavich in 1205 he dethroned his son and claimed the title himself. However in 1206 he was forced to run away, this time from Vsevolod Svyatoslavich (known as Vsevolod the Red)
6. In the same year he returned and took the city and the title back. But next year he ran away from Vsevolod's armies again.
7. And finally in 1207 he kicked Vsevolod from Kiev and took the title for the final time. In 1210 after negotiations with Vsevolod Yurievich the Big Nest he gave away his title to Vsevolod the Red again. Who knows how many times he would try to win the title but two years later Rurik died.

Aristide Briand was Prime Minister of France 6 non-contiguous times:

• Jul. 24, 1909 - Mar 2, 1911
• Jan 21, 1913 - Mar. 22, 1913
• Oct. 29, 1915 - Mar. 20, 1917
• Jan. 16, 1921 - Jan 15, 1922
• Nov. 28, 1925 - Jul. 20, 1926
• Jul. 29, 1929 - Nov. 2, 1929

for a total of eleven separate administrations:

• Briand's first Government, 24 July 1909 – 3 November 1910
• Briand's second Government, 3 November 1910 – 2 March 1911
• Briand's third and fourth Governments, 21 January – 22 March 1913
• Briand's fifth Government, 29 October 1915 – 12 December 1916
• Briand's sixth Government, 12 December 1916 – 20 March 1917
• Briand's seventh Government, 16 January 1921 – 15 January 1922
• Briand's eighth Government, 28 November 1925 – 9 March 1926
• Briand's ninth Government, 9 March – 23 June 1926
• Briand's tenth Government, 23 June – 19 July 1926
• Briand's eleventh Government, 29 July – 3 November 1929

_{Wikipedia: Aristide Briand}

Alexandre Ribot and Raymond Poincaré were Prime Minister of France 4 times.

Other Prime Ministers of France have held office on three distinct occasions:

• Gaston Doumergue
• Pierre Laval
• possibly others

Several Prime Ministers of Italy have held office on at least three non-contiguous occasions. Thanks to Denis Nardin, two individuals have been identified as Prime Minister of Italy on five non-contiguous occasions: - Amintore Fanfani; and - Giovanni Giolitti.