Audemars Piguet

So I was just reading something and am a little confused, hopefully someone can shine some light on this because the rest of the internet is being incredibly unhelpful. The first AP perpetual calendar, the 5516. The first time I saw it, it looked like thi...  

Hi Dylan, Well, you've picked quite the reference to zero in on - the ultimate vintage AP to be sure. It is my understanding that there were only eleven 5516s made, all in 1957. Not all of them featured a leap-year. Of those that did, six have the moonpha... 

Very detailed information.

Thanks for the response, that was even better than I expected. It doesn't seem like Christies even knew that haha. And if you don't mind my asking, how did you know this? I want access to whatever knowledge fountain you are using. Regards, Dylan

Hi Dylan, I have studied up a lot on this reference, as well as (of course!) the 5402. There is no single informational source I can point you to, but over time if you keep reading, asking questions, digging around in old texts, you will soon find yoursel... 

Well thank you very much! I'll keep asking questions when they come! Regards, Dylan