What is the meaning of "Four Gentlemen" in Beijing Opera "Four Gentlemen"?

During the Jiajing period of the Ming Dynasty, Mao Peng, Tianlun, Gu Du and Liu Ti, the new Jinshi, went out to Beijing as officials, and the four swore that they would never violate the law or neglect their duties after taking office, so as not to be squeezed out by Yan Song, the power phase. Yao, a resident of Shangcai County, Henan Province, was poisoned with poisoned wine by his sister-in-law, Tian Lun. Yao's wife, who later colluded with her brother, was sold to Yang Chun, a cloth seller. Under the willow tree, Young Souljaz found himself cheated by his brother and refused to go with Yang Chun. While they were arguing, they met Mao Peng (a tourist reporter from Bafu, Henan Province) disguised as a private tourist and asked why. Young Souljaz poured out his dissatisfaction. Yang Chun sympathized with Young Souljaz's experience and tore up her deed of sale on the spot, hoping to become brother and sister with Young Souljaz and accompany her to complain and take revenge. Mao Peng, pretending to be a fortune teller, wrote a letter of complaint for Young Souljaz, suggesting that they go to Xinyang to complain to Crescent Moon. Song Shijie worked as a bookkeeper in the government office of Xinyang Road, and opened a small hotel outside the west gate of Xinyang after retirement. On this day, he went out for a drink and met a group of hooligans who bullied Young Souljaz on the way. Song Shijie saw the unfairness and rescued Young Souljaz from the shop. Young Souljaz complained about her injustice, and Song Shijie and his wife accepted her as their adopted daughter. Song Shijie led Young Souljaz to complain to Xinyang Highway Bureau. After the complaint was handed in, Xinyang Gu Dao read Tianlun's letter, but turned black and white, defended the defendant and put Young Souljaz in prison. Song Shijie was beaten with forty sticks and expelled from the Taoist temple. Prior to this, Tian and Gu's bribery behavior had been confirmed, and in order to further crack down on Gu's reading behavior, he sued the inspector. Because Mao Peng learned the real situation of Young Souljaz's case in his private visit, he decided the case fairly and punished his brother who broke the law and discipline in the same year. None of them died.