Sparta had two kings, as part of its political structure. The dual kingship was a distinct feature of Spartan governance.
Spartan rulers shared authority, not only with one another but also with governing councils such as the Ephors (magistrates charged with supervising the kings) and the Gerousia (a council of elders), in contrast to other monarchs who possessed unbridled power. Leading the Spartans into combat was the majority of their responsibilities, but they also had important roles in religious events where they were revered as living examples of Spartan culture.
It’s interesting to note that, in contrast to the divine adoration accorded to kings in other Doric countries, such as Cyrene, Spartan monarchs were the only citizens to be honored with a hero worship after death. The only young Spartans who were excused from the Agoge—Sparta’s demanding educational and military training program—were their firstborn sons, who would go on to become kings. They were allowed to join, though, and they frequently did, maybe in an effort to strengthen their bonds with their fellow Spartans and get an understanding of the principles that underpinned the state.