It’s official: Grimes and Elon Musk have changed their baby’s name to comply with California law.

Earlier this month, the couple welcomed a baby boy into their family, and revealed his name to be ‘X Æ A-12’. But after reports emerged that California law does not allow the use of numbers in newly registered names, there were rumours that Grimes and Musk might have to find a new name. And they have, sort of. The child will be known by the similar, but slightly different, ‘X Æ A-Xii’.

While neither Grimes nor Musk have stated that the law is the reason that they changed the name, Grimes did respond to a question about it on Instagram, writing, “Roman numerals. Looks better tbh.”

Grimes previously explained the meaning behind the name, saying that the ‘X’ stands for “unknown variable”, and that ‘Æ’ is the Elven spelling of AI, meaning Artificial Intelligence. Grimes wrote, “It’s just X, like the letter X. Then AI. Like how you said the letter A then I.”

As Consequence of Sound points out, Elon Musk offered a different explanation while speaking on Joe Rogan’s podcast: “It’s just X, the letter X. And then, the Æ is, like, pronounced ‘Ash’… and then, A-12, A-12 is my contribution,” referring to the Lockheed A-12 OXCART aircraft.