The brek'tal ritual is a Klingon ritual that allows the widow of an honorably slain Klingon, who was the head of his House, to marry his opponent. If the ritual is performed the victor then becomes the head of his slain opponent's house. The brek'tal is only allowed when the former leader of the house dies without a male heir. Without the brek'tal the mistress, now widow, of the House may be granted special dispensation to lead the house on her own, but only if there are unique circumstances.
In 2371, Grilka, wife of Kozak, performed the brek'tal with Quark, a Ferengi, after Kozak died in a drunken fight with the barkeep. Leadership of Kozak's House temporarily passed to Quark before he ultimately got a divorce from Grilka and she took over its leadership. (DS9: "The House of Quark")