Each year, the participating postal ad- ministrations design their entries based on a theme chosen by PostEurop. On each occasion, Swiss Post issues two stamps in a sheet. One of these is entered into PostEurop’s international online competition. The competition will run from 9 May to 31 August 2017 at pos- teurop.org/europa2017.

Bellinzona’s castles and their forti ed walls form part of the UNESCO World Heritage Site. Their history dates back to the Palaeolithic Period. In the Middle Ages, they were initially intended to pre-vent the Swiss from gaining ground to the south. But in 1503, Bellinzona chose to withdraw from Milanese rule and in- stead joined the Swiss Confederation. In the following years the fortresses were used against the south.

Castelgrande – depicted on the right-hand stamp – is the oldest of the three castles and was rst mentioned in 590. From 1506 it became the seat of the federal gov- ernors of Canton Uri.

Castello Montebello is the forti cation in the middle. It was built towards the end of the 13th century, just as the Gotthard Pass was becoming the most important route across the Alps. It was home to the governors of Canton Schwyz.

Castello di Sasso Corbaro, shown on the left, is the smallest and newest of the three castles, but enjoys the most elevat- ed position. In 1506 the castle fell into the hands of Canton Nidwalden and re- mained there until it was passed on to newly founded Canton Ticino in 1803.

Issue Date: 11.05.2017
Designer: Davide Ackermann, Lugano
Printer: Gutenberg AG, Schaan, Liechtenstein
Process: Offset
Colours: 4 Colours
Size: Stamp: 40×28 mm, Sheetlet: 190×142 mm (4 rows of 5 stamps)