Marcus Aemilius Lepidus (c. 89 BC -13 BC or 12 BC) was an ancient Roman aristocratic politician who began ruling Rome in 43 BC and was one of the last three alliances.

Leipida is the son of Marcus Emilius Leipida the Elder. His father died during the Roman Civil War due to his involvement in a conspiracy against the Senate. Leipida went to seek refuge with Caesar, who was constantly growing in power, and became one of his most powerful supporters. With the support of Caesar, Leipida entered politics; He quickly stood out in the promotion system. In 49 BC, Lei Bida became a judge; When Caesar fought against the main army of Pompeii stationed in Spain, it was Leipida who replaced him in overseeing Rome. From 48 BC to 47 BC, Leipida was responsible for governing a part of Spain that was conquered by Caesar. Leipida faithfully worked for Caesar, and after Caesar defeated Pompey in the East, he managed to make Leipida elected consul in 46 BC. In February 44 BC, Caesar was declared a lifelong dictator by the Senate. Leipida was appointed as a cavalry officer by Caesar, which was an important position equivalent to Caesar's proxy.
The close relationship between Leipida and Caesar came to an end due to Caesar's sudden death. On March 15, 44 BC, Republican elders led by Brutus assassinated Caesar. One of the conspirators, Gaius Cassius Longinus, suggested killing Leipida and Mark Antony, who were important aides to Caesar, but Brutus refused, saying that what they did was an execution of the dictator, not a political conspiracy.

After Caesar's death, Leipida chose to follow Antony. At this time, there were three powerful figures of the Caesar faction: Anthony, Leipida, and Caesar's nephew and adopted son Octavian. In October of 43 BC, they openly formed a political alliance in Bologna, known as the last three headed alliance in history. The military capabilities of the three giants forced the Senate to recognize their power status and granted them legal power to rule Rome for 5 years. However, the three giants quickly began to eliminate their political enemies through "public enemy declarations"; In this political storm, 300 elders and 3000 knights were killed. As for the power of the republicans, it appeared to have been completely eradicated after the deaths of Cassius and Brutus. In 42 BC, Leipida served as the consul for the second time.
The latter three headed alliance is an unnatural alliance, with numerous conflicts among its members. Most of LeiBida's power was quickly taken away by two other people. After the Battle of Philippi, Rome was divided among the three heads, and Leipzig only obtained the provinces of Spain and Africa. He has always been careful to avoid getting involved in the sharp struggle between Anthony and Octavian. After the end of the 5-year rule period, the three members formed a new alliance through the Treaty of Tarentum in 38 BC and gained another 5-year rule; This time, Lepida is probably just a name in it. In 36 years ago, a wrong political move finally gave Octavian the opportunity to kick Leipida away; Leipida was stripped of military and political power, and only retained the religious title of the highest priest. Leipida retired from politics and later passed away peacefully during the reign of Octavian.
Leipida's wife Eunia is Brutus's sister. After the Battle of Philby, Leipida successfully saved her from being implicated in the campaign to eliminate the remnants of the Brutus Party.