Complex sentence: In 1894 when committee's for the museum came to be Allen was a major contributor who donated throughout his life and until he died in 1906 he steadily continued to add to the museum's collection.
Split into simpler sentences: In 1894 when the committee for the museum came to be, Allen was a major contributor who donated throughout his life and until he died in 1906. He steadily continued to add to the museum's collection.