Marian Albu, 40, of Harrow, north-west London, and Paul Popeanu, 34, of Heme l Hempstead , Hertfordshire, will appear at Kingston Crown Court on July 23, charged with conspiracy to burgle and remove criminal property from the UK.
The €2m theft of 260 rare books included incunabula, early books and manuscripts belonging to three dealers.
The stolen items had been destined for The California International Antiquarian Book Fair.
They were taken from trunks housed in a warehouse in Feltham, near Heathrow, on the night of January 29, 2017. It is unknown if any of the stolen material has been recovered.
A joint investigation team was established with Europol which led to 45 arrest warrants issued at addresses across Europe with 13 of them in the UK. As a result nine people were arrested in the UK and six in Romania.