text: Four teenage boys from this country formed an embassy sent by Alessandro Valignano to Gregory XIII.
full_question: Four teenage boys from this country formed an embassy sent by Alessandro Valignano to Gregory XIII. After the wreck of the San Felipe in this country led to rumors about spies, the twenty-six martyrs were crucified here. In this country, people had to trample on flat bronze carvings of Virgin Mary and Jesus to prove that they weren't Christian. After traveling from (*) India, the Jesuit priest Francis Xavier introduced Christianity to this country in 1549. Christian peasants in this country revolted in the Shimabara Rebellion shortly after its government implemented the sakoku policy of national seclusion. For 10 points, name this country where the Portuguese originally helped spread Christianity from the port of Nagasaki.
first_sentence: Four teenage boys from this country formed an embassy sent by Alessandro Valignano to Gregory XIII.
raw_answer: Japan