The traditional exchange with three Slavic Gymnasiums took place from 2nd – 6th March, 2015. This year the Diocesan Classical Gymnasium hosted students from Piarist Gxymnasium in Trenčín (Slovakia) and Piarist Lyceum from Krakow (Poland). Traditionally, students exchange their knowledge of singing as well as of all three Slavic mother tongues, namely Slovak, Polish and Slovene. The exchange ended with a concert of all three choirs and presentation of their language work.