Complex sentence: According to Markus Hiekkanen, the church was probably built in the 1440s, on the basis of the style of the closets; the gables were constructed about 50 years later.
Split into simpler sentences: According to Markus Hiekkanen, the church was probably built in the 1440s. On the basis of the style of the closets, the gables were constructed about 50 years later.