Modern tourism can be traced to what was known as the Grand Tour, which was a traditional trip around Europe (especially Germany and Italy), undertaken by mainly upper-class European young men of means, mainly from Western and Northern European countries. In 1624, the young Prince of Poland, Ladislaus Sigismund Vasa, the eldest son of Sigismund III, embarked on a journey across Europe, as was in custom among Polish nobility. He travelled through territories of today's Germany, Belgium, the Netherlands, where he admired the Siege of Breda by Spanish forces, France, Switzerland to Italy, Austria, and the Czech Republic. It was an educational journey and one of the outcomes was introduction of Italian opera in the Polish–Lithuanian Commonwealth.