Complex sentence: Historian A. P. Vlasto finds a Proto-Bulgarian flavour in the church's interior and thus a relation with the art of Persia or Central Asia and believes that it is not based on Byzantine examples of that age.
Split into simpler sentences: Historian A. P. Vlasto finds a Proto-Bulgarian flavour in the church's interior and a relation with the art of Persia or Central Asia. Thus, he believes that it is not based on Byzantine examples of that age.