Chronology of Catholic Dioceses:Notes on the See of Santo Domingo 1546 - 1848 - 1953
The See of Santo Domingo, established in 1511, was elevated to a Metropolitan Archdiocese in 1546. At that time, it was given suffragan dioceses around in the Caribbean area (like Santiago de Cuba, Puerto Rico and Coro), and later, more were established. Little by little, these dioceses were arranged differently - some became Metropolitan Archdioceses of their own right, others became attached to other Metropolitan Provinces.
In 1848, Santo Domingo`s only remaining suffragan, Puerto Rico, was made immediately suffragan to the Holy See. Thus, from 1848 to 1953, Santo Domingo was not a metropolitan see, but an Archdiocese wirhout suffragans.
In 1953, the Archdiocese of Santo Domingo - now covering all of but only the territory of the Dominican Republic - was divided, and the new dioceses of La Vega, San Juan de la Maguana, and Santiago de los Caballeros, were erected as suffragan dioceses of Santo Domingo.
This is why there are two dates for the erection of Santo Domingo as a Metropolitan See (1546 and 1953), since it became Metropolitan, ceased to be Metropolitan, and then again became a Metropolitan see.
-CT (with information from Charles N. Bransom)