In its Silk Road exhibition, the British Library shows the world’s earliest dated printed book, the Diamond Sutra. It contains an interesting colophon:

Reverently [caused to be] made for universal free distribution by Wang Jie on behalf of his two parents on the 13th of the 4th moon of the 9th year of Xiantong [i.e. 11th May, AD 868]

(My emphasis, of course.)