Austria 1850/1860 - Austria: First numbers on the envelope via Viaggiat

The complete set of six letters from Austria franked with stamps from the first issues and two used high-quality series from 1863/4.
A 6 kreuzer on the sheet margin is distinguished, a rare cancel on a 9 kreuzer blue for Trieste and a 2 kreuzer yellow on a nice fragment.
The letters present themselves in very good preservation condition.