It was created by the Royal Decree issued on the 5th February, 1625. Its main function was to stop the profligacy of granting undeserved mercies, which led to a significant expense borne by the Crown. It sought to ensure as much transparency as possible when it came to mercies and prevent at the same time that more than one mercy be granted for the same service by different bodies. By the Real Cédula issued on the 25th July of that same year, the viceroys and governors of the Indies were under an identical obligation. The secretary of the Royal Chamber was also the one in charge of the Secretaría de Registro (from Spanish “Recording Secretariat”), physically located in the palace next to the majority of the councils.

The Secretariat first disappeared on the 12th October, 1644 and was permanently dissolved on the 29th December 1691, when the documents from the secretariat were transported to the Royal Chamber of the Palace. Having been reborn in the 18th century (October 1706), it would then disappear by the Royal Decree issued on the 19th March, 1716. Its documentation was brought to the Contaduría de la Real Hacienda, which took over its powers.