The process by which Gowron became Chancellor of the Klingon High Council in 2367, with Jean-Luc Picard acting as Arbiter of Succession, and which set off the Klingon Civil War.
The ascension of Gowron is told across the Next Generation episodes Reunion and Redemption. Chancellor K'mpec, slowly poisoned by an unknown rival, appoints Picard as Arbiter of Succession so that an outsider will expose the poisoner and choose the next leader.
The candidates are Gowron, a political outsider, and Duras, whose family is secretly tied to the Romulans. A bomb at the ceremony points towards Duras, and the question is settled when Worf kills Duras to avenge K'Ehleyr.
Before Gowron can be installed, the Duras sisters Lursa and B'Etor produce Toral, an illegitimate son of Duras, and claim the chancellorship for him. Picard rules against the boy and completes the rite, most of the council walks out to join the House of Duras, and war follows. Gowron rewards the support of Worf and Kurn by restoring the honour of the House of Mogh.