Lawyers need to pass the legal professional qualification examination and legally obtain the lawyer's practice certificate before they can start practicing. It can be divided into full-time lawyers and part-time lawyers according to the nature of work; According to the business scope, there are civil lawyers, patent lawyers (double-certificate lawyers), criminal lawyers and administrative lawyers; According to the client and working status, it can be divided into social lawyers, corporate lawyers and public lawyers. Lawyer's business is mainly divided into litigation business and non-litigation business. The origin of lawyers can be traced back to the Roman period, 5 10 BC or 509 in the first 30 years. During this period, the lawsuit must be conducted according to the notice and legal procedures of the consul or legal officer. With the increasing number and complexity of laws and notices, the parties need the assistance of professionals familiar with the law in court debate, so defenders begin to rise. By the early days of the imperial system (65438 BC+the second half of the 20th century), defenders had become full-time lawyers and needed to study law and obtain qualifications in major cities. However, during the feudal period, most countries abolished the ancient debate litigation and adopted the inquisition instead, which led to the failure of lawyers. Some countries, such as France in the early Middle Ages, retained the lawyer system, but it was mainly applicable to religious courts, and the position of lawyer was held by monks. Although monks were forbidden to act as defenders in French secular courts after the12nd century, they were replaced by professional lawyers with feudal legal education, who took the oath and registered, but their authority was still greatly restricted and ineffective.