In the Middle Ages, all children in a family were often given the same name. The Polish chronicler Jan Dlugosz had ten brothers with the same name. And at the aristocratic Christmas feast in the city of Bayeux (Northern France) in 1171, 117 Wilhelms gathered.
9th place: In Russia, back in the XII century, noble women were named either by their father ("Yaroslavna"), or by their husband ("Glebovaya").
8th place: Boris Godunov was the first to introduce the name Xenia into the royal family.
7th place: Peter I tried to be a "pioneer" everywhere, including naming his own children. He named one of his daughters Margarita, a name that at that time was found in Russia only among nuns. This name is still very beloved in those countries where hereditary royal power exists: in England, Holland and Belgium.
6th place: Peter was the first to introduce the names of Paul and Alexander into the names of the reigning dynasty. Prior to that, the name Alexander was found in Russia only in antiquity. After Peter and to this day, the name Alexander remains one of the most popular.
5th place: For a long time there was no name Andrei in the Russian tsarist dynasties. It is also not found in other august houses. Is that there were a couple of Andreev on the throne of Venice and now - the already mentioned British Prince Andrew.
4th place: The name Tatiana, which, according to some, has always been common (and allegedly it was Pushkin who introduced it into fashion), on the contrary, was often found in the names of the royal house. Tatyans were already among the first Romanovs, in the families of Tsars Mikhail and Alexei.
3rd place: The choice of names for the royal offspring is strictly similar everywhere. In Spain, only once, in 1886, Queen Christina, against the advice of the Court, named her son Alfonso, but this name turned out to be unlucky, as the courtiers predicted. King Alphonse XIII did not rule for long and abdicated the throne.
2nd place: There are only 2 male royal names in Denmark: Frederick and Christian, which alternate. It is not customary to call the prince who will become king by other names.
1st place: In Japan, the name of the emperor is determined by the council of sages-scribes. Moreover, this name has nothing to do with the name that the emperor received at birth. For example, the council named Emperor Hirohito the name Showa, which means "Enlightened World". Emperor Akihito after death will receive the name Heisei, which translates as "Peace and Tranquility".