Complex sentence: He went on to King's College London (at age 15) and Trinity College, Cambridge, where he was elected fellow in 1868, after being second wrangler in 1867 and second Smith's prizeman.
Split into simpler sentences: He went on to King's College London (at age 15) and Trinity College, Cambridge. At the latter, he was second wrangler in 1867 and second Smith's prizeman.