A tribe that formed a prestigious tribal kingdom centuries earlier; by the Prophet ﷺ's time it had lost that status but remained a large tribe.
The Prophet ﷺ was going around the tribes at Mina during the pilgrimage season, looking for a tribe that would protect him. He approached one of the chiefs of Kindah. Kindah had been a powerful tribal kingdom a few hundred years earlier, and though it had lost that status, it was still a large tribe. The chief listened carefully and found the message interesting. He brought the Prophet ﷺ before the other chiefs of Kindah so that they could hear it too. The chief then told his fellow tribesmen that if they took up this message, they could use it to conquer the other Arabs. He was thinking in terms of power, not faith. He asked the Prophet ﷺ whether, if they followed him and Allah gave them victory, Kindah would rule after him. The Prophet ﷺ answered, "The kingdom belongs to Allah, and Allah gives it to whomever He pleases." The chief replied that Kindah would be risking their necks for him, only for him to take the kingdom after they had shed their blood. He told the Prophet ﷺ to go, saying they had no need of this.
While the Prophet ﷺ was camped at Tabuk, he sent Khalid ibn al-Walid RA with a few hundred sahaba (companions) on a small expedition to Dawmat al-Jandal. This was the home of the Christian Arab tribe of Kindah, which had close ties with the Roman emperor. Their chieftain, Ukaydir ibn Abd al-Malik, was called a king (malik). The Prophet ﷺ told Khalid that he would find Ukaydir away from his entourage, in the middle of some cows. That is exactly what happened. One night Ukaydir's herd of cows kept barging against the door of his palace. His wife grew fed up and told him to deal with it, so he went out himself with a few servants. Khalid found him there in the open and captured him. Ukaydir was brought before the Prophet ﷺ. He did not embrace Islam at that time. He did agree to break off his ties with the Romans, to pay the jizya (a tax paid by non-Muslims under Muslim protection), and not to attack the Muslims. To show his loyalty, he later sent gifts to the Muslim camp. Among them was a hulla, a fine two-piece garment with gold thread, more beautiful than anything the companions had seen. The Prophet ﷺ wore it, and the companions gathered around it in awe.