Both Aurelius and Natalia were Christians martyred under the reign of Abd ar-Rahman II, Emir of Cordoba.
Saint Aurelius was born to a Muslim father and Christian father and for a while kept his faith in Christ a secret. He married his wife Saint Natalia who also was forced for a time to keep her faith secret as her father was likewise a Muslim. Saint Aurelius had a cousin, Felix, who professed Islam for many years but converted back to Christianity when he married his wife Lillosa. The four began to openly profess their faith during a time of strict sharia law enforced by the Emir, Abd ar-Rahman II, going so far as the two women refusing to wear veils over their faces while in public.
All four were arrested and brought to the Emir's court. Charged as being apostates from Islam, the group faced public executions if they did not recant their Christian faith. Joining them in their prison was a local monk, George who had spoken publicly against Muhammad. Because he was a foreigner, George could have been allowed a pardon and passage out of Cordoba. He joined the four others, however, in refusing to recant their Christian faith. All five were lead to the square and beheaded in 852 AD.
Both the Roman Catholic Church and Eastern Orthodox Church celebrate their feast day on July 27th.