St. Peter's Pro-Cathedral
Peter's Church , also known as St . Peter's Pro-Cathedral , was a historic church in Baltimore , Maryland that served as the first Catholic pro-cathedral in the United States; first built in 1770 , the church became the pro-cathedral of the Diocese of Baltimore when the diocese was created in 1789 , and the seat of Archbishop John Carroll , the first Catholic bishop in the United States . 
<triplet> St. Peter's Pro-Cathedral <subj> Baltimore, Maryland <obj> located in the administrative territorial entity <subj> 1770 <obj> inception <subj> Diocese of Baltimore <obj> diocese <triplet> Diocese of Baltimore <subj> Baltimore, Maryland <obj> headquarters location <subj> 1789 <obj> inception