Short answers, pulled from the story.
The Holy See traces its origins to the first century when Saint Peter and Saint Paul established the Diocese of Rome. Catholic tradition holds that this apostolic see became the focal point for all Catholics worldwide through doctrines of Petrine primacy.
In 313, Roman Emperor Constantine the Great issued the Edict of Milan which legally recognized the Church and its property rights within the empire. This legal recognition marked a turning point in the relationship between religious authority and imperial power.
The Lateran Treaty signed in 1929 between the Holy See and the Kingdom of Italy resolved the Roman Question by establishing Vatican City State as an independent city-state. This agreement granted the Holy See full ownership exclusive dominion and sovereign authority over the new territory.
Cardinal Pietro Parolin serves as Cardinal Secretary of State since being named by Pope Francis on the 31st of August 2013. He functions as the chief administrator of the Roman Curia which includes nineteen dicasteries comparable to executive departments.
The Holy See maintains formal diplomatic relations with one hundred eighty sovereign states plus the European Union and Palestine Liberation Organization. Sixty-nine diplomatic missions accredited to the Holy See operate from Rome while another one hundred eight permanent missions function abroad.