Complex sentence: Petrus Särkilahti (died 1529, sometimes written as "Petrus Saerkilahti"), Martin Luther's first Finnish student, was one of the early pioneers of teaching science in Finnish language.
Split into simpler sentences: Petrus Särkilahti (a.k.a. Pietari Särkilahti), sometimes written as "Petrus Saerkilahti", died in 1529. He was Martin Luther's first Finnish student and one of the early pioneers of teaching science in Finnish language.