Hadrian's Wall and a birthday

We are celebrating a birthday in our house today.
 
The first known birthday card is said to be a wooden tablet found at the Roman fort Vindolanda, on Hadrian’s Wall. It’s an invitation to her birthday celebration from Claudia Severa to her friend Sulpicia Lepidina, written in about 100 AD. Strictly speaking, then, it’s not what we would now describe as a birthday card. But it’s significant because the Romans were, as far as we know, the first people to celebrate ordinary people’s birthdays – as distinct from the birthdays of gods and emperors.
 
Claudia Severa’s tablet is also significant because she was literate and this is the earliest known example of a woman writing in Latin.
 
The photo shows the birthday girl at Hadrian’s Wall on a cold day in October 2015. The extra is in the café at Vindolanda.