Porphyrogenitus

Porphyrogenitus is a prestigious title held by male children of a primarch, who were born during the reign of their ruling parent. The female version of the title is porphyrogenita and is completely equal to the male version. Porphyrogenita can belong to either the Imperial Family of Palaven or a primatial family of one of the empire's extrasolar colonies. The title is automatically bestowed upon birth and cannot be removed unless the bearer is disowned by their ruling parent. Porphyrogenitus translates as "born in the purple", a reference to the fact that wearing the colour purple is restricted by law to royalty. 
The title predates the creation of Aurelion's empire and its hierarchical meritocracy, and once denoted the senior heirs of the ruling Imperator of Palaven. Aurelion expanded the use of the title to the colonies, authorising its use by the children of colonial primarchs for the first time in history in a bid to make colonial citizens feel equal to imperial citizens. Despite the title now being purely symbolic, there is still a societal expectation that those who bear it are destined for a prominent role in service to the empire. Those who fail to live up to those expectations bring shame to the ruling parent. 
A child born before their parent became a primarch cannot hold the title, even if they are of legitimate birth. Likewise, an illegitimate child born during their ruling parent's reign cannot hold the title either. 
As primarchs tend to be older by the time of their anointing, Porphyrogenita are somewhat rare and are usually the product of second or third marriages in later life. 
== List of known Porphyrogenita ==
=== Imperial Porphyrogenita ===
* Trebia Aurelos - daughter of Aurelion Aurelos and his wife, Septonia Halabrian.
* Regnaltus Fedorian II - son of Regnaltus Fedorian I and his second wife, Melaira Mehrkuri.
* Malkum Victus - son of Adrien Victus and his second wife, Iacoba Parvus.
* Aritaea Victus - daughter of Adrien Victus and his second wife, Iacoba Parvus.
* Keirix Victus - son of Fidellion Victus and his second wife, Marcia Abrudas.
* Adriana Victus - daughter of Fidellion Victus and his second wife, Marcia Abrudas.
* Irixia Victus - daughter of Fidellion Victus and his second wife, Marcia Abrudas.
* Gaius Victus - son of Fidellion Victus and his second wife, Marcia Abrudas.
=== Colonial Porphyrogenita ===
* Aurelion "Auri" Abrudas - son of Markus Abrudas and his wife, Trebia Aurelos. Member of the Primatial Family of Carthaan.
* Astraeus Mehrkuri - son of Astraea Mehrkuri and her husband, Antraxes Partinax. Member of the Primatial Family of Digeris.