A little information that i have read on wikipedia, persian cats are a breed of long haired domestic cat with a round face and short snout. The name refers to persia, the old name of iran, where similiar cats were found. Since the late 19th century, this type of cat was developed in great britain and the united states after world war II.
Apart from that, persian cats have a sweet, gentle character and easily get along with humans. Persian cats are also cats that are easy to adapt to, so it is not surprising that persian cats are cats that are often kept.