VATICAN CITY — The Catholic Church awoke Friday with no leader following the resignation of Benedict XVI, who pledged obedience to his successor and described himself as "simply a pilgrim" starting the final journey of his life.

Now begins a period known as the "sede vacante" or "vacant see" — the transition between the end of one papacy and the start of another.

During this limited time, several key players take charge of running the Holy See, guiding the College of Cardinals in their deliberations and organizing the conclave of cardinals whose votes elect Benedict's successor.