Complex sentence: He was first married in to Bertha M. Levy (b.1867); from this he had the children Beatrice Danziger (1891-1974, married to William K. Dolan) and Nathan Danziger (1894-1965), who changed his name to Nathaniel Dolan.
Split into simpler sentences: He was first married in to Bertha M. Levy (b.1867). From his first marriage he had the children Beatrice Danziger (1891-1974, married to William K. Dolan) and Nathan Danziger (1894-1965), who changed his name to Nathaniel Dolan.