The Tres Bohemes website, a good source for all things Czech – and some Slovak – does a better job than I can, so I’ll refer you to them here.
Also, September 7 was the four-hundredth anniversary of the deaths of three priests executed during the uprisings led by Gabriel Betlan in what was then Hungary, in today's East Slovak city Košice, the second largest municipality in the country. They were canonized by John Paul II during his visit to Slovakia in 1995. (I was living in the country at the time, but did not see the pontiff there, though I did see him in the Vatican the year before while traveling with a Slovak chorus.)
There were several special Masses for the occasion. The St. Cecilia choir I sang in from 1996-97 performed at one of those events, held in the "Premonstratensian" church which was built on the site of their martyrdom. I've sung with the group in that church in several concerts there, as well as for the wedding of one chorus member.
Curiously, none of the three martyrs was Slovak: Marek Križin was Croatian, Štefan Pongrác Hungarian, and Melichar Grodeckzý Polish. As a spokesman for the diocese recently pointed out, this fact symbolizes the supranational position of the Church. And in another sense, all three were Košice people, so all the town's citizens can be proud.