A more thorough explanation:

Definition: Vicarius Apostolicus is a Latin term that means "apostolic vicar." In Ecclesiastical law, it refers to an officer who represents the Pope and exercises his authority in remote regions. This officer may be sent to provinces where there is no bishop or where the see has been vacant for a long time.

• When the bishop of a remote region retired, the Pope appointed a vicarius apostolicus to oversee the diocese until a new bishop could be appointed.
• In some countries, there are areas where the Catholic Church is not well established. In these regions, a vicarius apostolicus may be appointed to help establish and grow the Church.

These examples illustrate how a vicarius apostolicus can be appointed to serve in areas where there is a need for spiritual guidance and leadership. They also show how this officer can help to establish and grow the Catholic Church in regions where it may not be well established.