Complex sentence: Chiryū-juku was well known as a horse trading town, so when Hiroshige painted the post town for "The Fifty-Three Stations of the Tōkaidō", he entitled the work "Summer Horse Market" (首夏馬市 "Shuka Umaichi").
Split into simpler sentences: Chiryū-juku was well known as a horse trading town. When Hiroshige painted the post town for "The Fifty-Three Stations of the Tōkaidō", he entitled the work "Summer Horse Market" (首夏馬市 "Shuka Umaichi").