田常 / Tian Chang
田常 / Tian Chang appears in 《资治通鉴·周纪》57丨古代发毒誓还有这作用？ as the 齐国 chief minister whom 子贡 / 端木赐 persuades during the effort to save 鲁国. The episode presents him as the first lever in Zigong’s chain: if Tian Chang can be moved away from attacking weak Lu, the immediate danger to Lu can be displaced into a larger strategic field.
The page is source-scoped. Tian Chang’s function in this telling is to show that successful rescue diplomacy begins by reading the decision-maker’s incentives, not by pleading for mercy in the abstract.