Complex sentence: The skomorokhs appeared in Kievan Rus no later than the mid- 11th century, however, fresco depictions of skomorokh musicians in the Saint Sophia Cathedral in Kiev which previously were thought to be dated to the 11th century have been recently shown to have been done in 1848.
Split into simpler sentences: The skomorokhs appeared in Kievan Rus no later than in the mid- 11th century. Fresco depictions of skomorokh musicians in the Saint Sophia Cathedral in Kiev which previously were thopught to be dated to the 11th centruy have been recently shown to have been done in 1848.