The title "Apostle of the Germans" refers to Saint Boniface, an English missionary who played a crucial role in spreading Christianity in what is now Germany during the 8th century. He is known for his efforts to convert the pagan Germanic tribes and establish a structured church in the region. His work included founding monasteries and promoting education. Saint Boniface is also recognized for his dedication to reforming the church and aligning it with Roman practices. He was martyred in 754 while on a missionary journey, and his legacy continues to influence Christianity in Germany today.