The card is contemporary, the location definitely not.  Google provides this:  Constantine the Great reputedly built the original cistern on this site, with the current one being enlarged and rebuilt by Justinian in 532. It was known as the Basilica Cistern after the Stoa Basilica, which used to stand above it.  As for the 4-3/4″ x 6-5/8″ card, we have two of them.  One was mailed with a postage meter in 2010 (Grade: 1, $3).  The other is unused (Grade: 1, $2).