Before Javier Olivares joined, the project had little historical accuracy and gave more importance to romance. Gonzalo de Córdoba had an unhistorical sexual relationship with Isabel before her marriage, and the first season ended with her wedding to Fernando in 1469. Olivares pushed for more politics, gave more importance to the character of Isabel's mentor, Gonzalo Chacón, and set the finale in 1474, with Isabel's coronation.
The word "Spain" is never said.
According to Javier Olivares, the dialogue in each episode of the first season has an average of 12 sentences lifted from documents of the time, such as letters written by the characters or contemporary chronicles like Alonso de Palencia's.
For the third and final season, the network wanted to show plenty of Christopher Columbus arriving to America, but the budget didn't allow it. They tried to co-produce the season with a Latinamerican country, but the negotiations didn't arrive anywhere.