This is a Dutch East Indies 1859 Pre Stamp Full Letter, written in Dutch.  It was sent to Batavia, with M/S shipping instructions.

This cover has a boxed ZEEBRIEF ONGEFRANKEERED mark in red 76c.  It's not particularly strong, but it is there.  This is a lovely and well preserved early cover!

Take care because this item, though in very good shape, is still extremely old!