Achish

Achish son of Moach was the Philistine king of Gath to whom David, having had enough of being ran around by an unrelenting Saul, turned to offer his service as a vassal warrior (1 Sam 21-29). So confident did Achish become of David's loyalty to him, he took him along as part of his army when he set off with the other Philistine kings to fight against Saul and the Israelite army. Eventually, however, David was sent back home because the other Philistine leaders felt uncomfortable with him.

Towards the end of David's life, long after he had subdued the Philistines confederacy. Shimei son of Gera, who had been ordered by David, through Solomon, to confine his stay within Jerusalem; "The day you leave and cross the Kidron Valley, you can be sure you will die; your blood will be on your own head," Solomon had commanded (1 Ki 2:37). One day, however, Shimei was told that two of his slaves had run off to Achish son of Maacah. Foolishly Archish left for Gath to look for his slave. Technically speaking, he had not disobeyed Solomon since the journey to Gath (in the west) did not require crossing the Kidron Valley (in the east). Upon his return, however, he was summoned by Solomon, found guilty of transgression and put to death. It is not possible to tell if this Philistine king was the same person the earlier king because the two names Moach and Maacah are just different forms of the same Hebrew name.