Complex sentence: Early in the twentieth century, the first marquis Antonio López y López invited King Alfonso XII to his mansion at Comillas and the town became popular with the aristocracy; the architect Joan Martorell built the enormous Palacio de Sobrellano on the instructions of the marquis.
Split into simpler sentences: Early in the twentieth century, the first marquis Antonio López y López invited King Alfonso XII to his mansion at Comillas and the town became popular with the aristocracy. The architect Joan Martorell built the enormous Palacio de Sobrellano on the instructions of the marquis.