Delft tiles arrived in Puerto Rico after 1648, from trade with the Netherlands Antilles. Elmer Adler saw they were used in some Spanish Colonial dwellings and churches from different parts of the island. During the building rehabilitation he bought antique tiles from Delft to be installed on the stairs of the museum.
Curious fact: Adler was from New York State, where the Dutch established the colony of New Amsterdam on Manhattan Island in 1626.