The Infanta Cristina became the first relative of the Spanish monarch ever to stand trial on Monday as legal proceedings in a tax fraud case opened against her and 17 others in Palma de Mallorca.
The 50-year-old sister of King Felipe VI was stripped of her duchess title due to the embezzlement charges, which she faces as an accessory to her husband Inaki Urdangarin, 47.
Urdangarin, a former Olympic handball player, is accused of embezzling about 6 million euros (6.8 million dollars) in public funds through a charity, the Noos Institute, which he ran from 2004 to 2006. Cristina allegedly helped him withhold income tax in 2007 and 2008.
The couple met an hour before the proceedings were due to start at the court venue, which is a plain classroom in Mallorca's Administration School instead of a courtroom due to space constraints. The school lies right next to the island's prison.
Cristina took her place in the furthest corner in the back row of the seating area for the accused, who got to sit on blue upholstered chairs instead of the usual wooden benches. The placement means she sees a portrait of her brother every time she looks at the judges.
Urdangarin's business partner, Diego Torres, is among the total of 18 accused in the case.
Cristina, known as the Infanta, was sixth in line to the throne. Many say her father, Juan Carlos, would possibly not have abdicated in June 2014 if it had not been for the scandal. The trial is expected to reveal exactly what the royal family knew about Urdangarin's business dealings.
Cristina had received the title of duchess from her father when she married Urdangarin, in 1997. Urdangarin was named the duke of Palma de Mallorca at the time. The couple now no longer belong officially to the royal family and Felipe has reduced contact with his sister to a minimum.
The royal family has maintained silence throughout the scandal and is unlikely to make a statement in the future.
Prosecutors are seeking a 20-year prison sentence for Urdangarin.
The defence is expected to ask for the case against Cristina to be dismissed, arguing that both the prosecution and the tax authorities were opposed to the indictment against her.
They will also say that the charges were based solely on the actions of the trade union Manos Limpias (Clean Hands), which fights corruption and is acting as joint plaintiff in the case. It is seeking eight years and a fine of 2 million euros against her.
The trial is expected to last until June, but could end sooner if individual defendants strike deals with the prosecution. The former head of the government of the Balearic Islands Jaume Matas is seeking just such a deal to reduce the 11-year sentence demanded against him.