[3][4][5] Prior to the establishment of the Capitol, the Legislative Assembly used the Provincial Delegation Building, which now houses the Department of State.

[6] The idea of constructing a capitol was first introduced by former Resident Commissioner Luis Muñoz Rivera in 1907, and was partly meant to demonstrate some degree of civilian rule in the island, which at the time was already a colony of the United States.

[7] The project proposed by Muñoz Rivera assigned $3 million for the construction and established rules for a contest among architectures to decide which one would do the work.

In September 1907, Commissioner of the Interior Laurence Grahame sent the official request for architects through the press and magazines of United States.

However, Luis Muñoz Rivera and the local press preferred another project that was disqualified by the evaluating committee, because the architect had included a slogan in the blueprints, which was forbidden.

With the supervision of architects Adrian C. Finlayson, Francisco Roldán, and Pedro de Castro, new blueprints were made using the Renaissance style.

When Finlayson got ill, he was replaced by Rafael Carmoega who, along with architects Joseph O'Kelly, William Schimmelpfennig, Harry Pembleton, Albert Nichols, Luis F. Pina, and Gonzalo Fernós Maldonado, made another design to finish the structure.

There is also a proposal for the surrounding gardens by the architectural firm of Bennet, Parsons and Frost and several plates showing entries for the building competition.