Laudetur Jesus Christus!
Dear Alex, I think it is rather difficult to be absolutely sure about ethnical self-identity of the Pratulin Martyrs. No doubts that they were eastern catholic from the byzantine eparchy of Kholm, but they were persecuted because they opposed forced "easternization" of theirs heavily latinized church ( parish and eparchy as well), and then were killed by russian Cossacks because rejected in 1874 forced inclusion of the eparchy into russian orthodox church. There were many more martyrs in Kholm eparchy. They were not necessarily killed, but persecuted, jailed, fined, etc. Officially all faithful were considerd orthodox and in tsarist Russia to abandon orthodox church was a crime. But most of the faithful didn't want to accept religious services from the hands of orthodox priests. They sought help from illegal, from russian POV, latin priest. They were able to wait some years to baptize a child by latin priest, but they had to hide this child before russian authorities, to avoid baptism in orthodox church. When latin priest was not accesible they buried theirs deceased without priest at all. But these had to be clandestine burials with no graves left. Otherwise authorities digged the body out and arranged an orthodox burial. Was this the case nobody from family members attended such "official" burial. They endured 30 years of this kind of sufferings. In 1905 Tsar was forced, due to revolution in Russia, to proclaim edict of tolerance. Eastern catholicism was still illegal, but it was allowed to leave orthodoxy. 200.000 former eastern catholics joined with joy latin church. I think their resistance and then choice of latin catholicism was due to the fact, that no matter who their ancestor were, they identified themselvs as catholics and Polish.
This history is well described by Wladyslaw Reymont, polish writer who won Nobel Price in 1924, in a book "From the Kholm Land" which I read recently, but I think it was not translated in english.
So I think there are some reasons why Poles celebrates them also as their saints. Veneration of Pratulin Martyrs is vivid in byzantine-slavonic parish of Kostomloty, but their relics are preserved in now latin rite parish of Pratulin. Both these parishes are on the west bank of the river Bug, just on the very border between Polan And Belorussia. I visited both during my last summer hollidays.
In Christ
Piotr
