Axion estin - so called Tsar Theodor's chant in it's original Byzantine version and polyphonic set

For more than three centuries, this melody was attributed to Tsar Fyodor Romanov. A year ago, I discovered the original version of this melody in a 17th-century post-Byzantine manuscript. A month ago, I found the same melody in a Ukrainian irmologion. The reason it was attributed to Tsar Fyodor is simply because it was written down in his personal irmologion and also appeared in a polyphonic arrangement in one of the manuscripts from the time of Tsar Fyodor. You will hear this polyphonic version in a Polish-language edition.