The Capellans were a humanoid species native to the planet Capella IV. As of the 23rd century, their civilization was divided into Ten Tribes, all led by the High Teer. The position of Teer was normally hereditary, but could be taken by the winner of a successful challenge to the death. Sometimes such challenges involved large numbers of people fighting on both sides of the question.
In the later 23rd century, Capellan men wore tight fitting garb that covered nearly their entire bodies, generally leaving only the face and hands exposed. The hair was pulled into a kind of topknot through an opening in the top of the headgear. Male attire is very colorful, but there is no indication that color connoted status. More important Capellans added subdued ornamentation to their clothing; typically, this consisted of fringes or ruffs of fur. Capellan women wore long, flowing dresses and bound their hair.
Capellans were tall and large; seven feet was not unusual. They were also fast and strong.
Capellan society was bound by a wide variety of rules and strictures, violation of which could have consequences as severe as death. A few of these included:
- No other man may touch the wife of a Teer. Doing so was punishable by death.
- The heir of a deposed Teer was traditionally killed by the usurper; if the heir was not yet born, then the mother was killed before birth could occur.
- If a woman offered a man fruit, and he accepted, her nearest male relative must try to kill the recipient. This form of challenge was considered an honor; the Capellans valued combat even over love.
- Capellans valued honesty, and accepted the word even of strangers. But if one's word was proved valueless, the offended Capellan would try to kill the offender. To say that someone's word was unimportant, and that you do not hear him was equivalent to accusing him of lying.
- Capellans valued hospitality, and demonstrated it to anyone who did not give them reason to consider him an enemy.
- Capellans valued the courageous, and disdained the fearful.
- Capellans believed that the strong should survive, and the weak and sick died. They had little use for doctors or medicines.
- When aroused to anger, a Capellan acted quickly; he did not stop to ponder his course of action, but usually simply attacked whoever had angered or offended him.
Capellan language and names often contained a double vowel combination; this often broke the word into extra syllables.
Capellans fought hand to hand with swords and knives. At ranges of up to one hundred yards, they could accurately throw a three bladed disc called a kleegat; this weapon, in the hands of a skilled user, was deadly.
The Capellans had been aware of space-going society since at least the 23rd century, when Leonard McCoy visited their homeworld as part of a medical assistance team. In 2267, a series of events involving a Klingon agent, Kras, and Captain Kirk led to the signing of a mining treaty between the Federation and the Teer of the Ten Tribes – at that time, the infant Leonard James Akaar was born. (TOS: "Friday's Child")