Its Comstar Precentor Fochs' official challenge (based on the Clan's " to IlKhan (head Khan of the clans) Ulric Kerensky of the time, place, and victory conditions.
(Excerpt from Sarna.net (Battletech Wiki))
The invading Clans realized they would need to elect a new ilKhan to lead the invasion, but such a process could only take place with a vote of all the
Bloodnamed warriors, forcing them to return to their homeworlds. This process took a year to complete and gave the Inner Sphere breathing room to rebuild and prepare. Now led by
Ulric Kerensky of Clan Wolf, the fifth wave of the invasion began in November
3051 and again threatened to sweep through the Inner Sphere. However, it was also during this time that ilKhan Kerensky revealed to
ComStar the goal of their invasion was
Terra herself. Up to this point ComStar had been "neutral" in the conflict, even aiding the Clans in the administration of their conquered worlds. But with their seat of power threatened,
Precentor Martial Anastasius Focht made a daring proposal. The
Com Guards would fight the Clans at a neutral site to decide the fate of the invasion: if they won the Clans would agree to a fifteen-year long truce, if they lost then Terra was theirs. The resulting
Battle of Tukayyid was a resounding victory for ComStar and brought about an end to Operation Revival. (End Article)
Shortly before the 15-year "Truce of Tukayyid" ended, the Civil War between Victor Steiner-Davion, and his sister Katrina Steiner-Davion began, starting with Katrina's assassination of their own mother, the matriarch of the Federated Commonwealth (formerly the Federated Suns and Lyran Commonwealth). Victor and the massive armada of Operation Bulldog had left the Inner Sphere for the Clan Homeworlds two years prior and had since been successful in the complete destruction of Clan Smoke Jaguar, and had raised a Star League flag over the Clan Capital of Strana Mechty. This effectively halted the Clan invasion permanently, leading to HUGE changes for both the Inner Sphere, and the Clans. Victor came home to his brother's being assassinated, and falsified evidence linking himself to both his mother's and brother's assassinations. With the help of allies from other great houses, Victor eventually uncovered the truth, exposing his sister, who eventually disappeared deep into Clan space (and picked up by Vlad Ward, the new Khan of Clan Wolf).