A few extra bits to add to sds' answer...
1. Historical figures with twins.
There are a couple of notable omissions from the Wikipedia list:
COMMODUS (born 31st August 161, died 31st December 192 AD) had an elder twin brother, Titus Aurelius Fulvus Antoninus. This double arrival was evidently viewed postively for
The astrologers cast favourable horoscopes for both of them. The event
was appropriately celebrated on the imperial coinage.
Source: Anthony Birley, Marcus Aurelius: A Biography
Silver denarius of Faustina II (wife of Marcus Aurelius). This coin commemorates the birth of twin boys
Despite the astrologers and their horoscopes, the elder twin died in 165 AD. Their parents, Marcus Aurelius and Faustina the Younger, also had twins (Titus Aelius Antoninus and Titus Aelius Aurelius) in 149 AD. The twins were
commemorated on the coinage of the year, with, on the reverse, crossed
cornucopiae surmounted by busts of two small boys, and the legend
temporum felicitas, ‘the happiness of the times’. But first one of the
infants died, then the second, both before the end of 149.
HENRY II of Castile (born 13th January 1334, died 29th May 1379) had a younger twin brother, Fadrique Alfonso, Lord of Haro (died 29 May 1358). They were the illegitimate sons of Alfonso XI of Castile. When their father died, he was succeeded by the twins' half brother Peter of Castile (known both as 'the cruel' and 'the just'). After the twins' mother was executed, they rebelled and were reconciled with Peter several times. Then, in 1358, Fadrique was apparently lured to his death by Peter. Henry continued to rebel (it gets complicated) until, in 1369, he personally killed his half-brother Peter after having defeated him at the Battle of Montiel.
2. Why are twins so rare among historical figures?
It is difficult to establish just how rare such births were as we simply don't have any statistics but it is fair to say that, prior to the advent of modern medicine, few such births were successful. Pliny the Elder noted that
when twins are born, it is rare for the mother or more than one baby
According to Pliny, the mortality rate was especially high if one twin was male and the other female, with only a one-in-ten chance of both surviving.
While the Romans may have seen twins as a cause for celebration, medieval Europeans seem to have had mixed views with some regarding twins as being the result of adultery or as being unnatural, but at the same time they were also "revered...as people with special powers". One (anonymous) 14th century Hebrew writer classifies these births as 'difficult', as when
the foetus is dead, or when his head is very big, or when he has two
heads, or when there are / twins, or when the birth is unnatural, or
when it occurs before time, or when the woman is very old, or as a
result of the uterus’ diseases
The Trotula Manuscript, "the earliest obstetric work in Middle English" (15th century translation), in giving instructions to midwives on delivering twins, alludes to the high mortality rate when it says "the children brought to grief, as often happens."
Twins are more likely to be born prematurely, weigh less and be at
more risk of childhood death than singleton babies, all of which can
cause health problems later in life.
Given the already high infant mortality rates of even single births persisted into the 20th century, it is hardly surprising that few twins survived. Further, in ancient Japan, A. Piontelli notes that (with reference to infanticide)
twins were not welcome in ancient Japan. Their mothers were regarded
as animal-like, as twins were associated with animal litters, and the twins spoiled their mothers' bodies and imposed financial hardship on the family.
If the incidence of twins in ancient Japan was roughly the same as just before the advent of fertility treatment (approx. 5.5 to 7 per 1000 births, compared about 10 per 1000 births in France, Germany and the UK), it is no surprise that few survived.