A more thorough explanation:

Duodecima manus is a Latin term that means "twelve men." In the past, when someone had to prove their innocence in court, they would bring eleven of their neighbors with them to swear that they believed the person was telling the truth. This group of twelve people was called the duodecima manus. The idea was that if twelve people all agreed that someone was telling the truth, then it was more likely to be true. This practice was used in England in the past, and it was called "wager of law." For example, if someone was accused of stealing a cow, they could use the wager of law to prove their innocence. They would bring eleven of their neighbors to swear that they believed the person did not steal the cow. The duodecima manus was an important part of the legal system in the past, but it is not used anymore.