Complex sentence: The Commission of Fine Arts suggested a design competition under its auspices, but its recommendations were rejected by the Treasury Department, which Taxay ascribes to an unwillingness to dishonor Sinnock.
Split into simpler sentences: The Commission of Fine Arts suggested a design competition under its auspices. However, its recommendations were rejected by the Treasury Department, which Taxay ascribes to an unwillingness to dishonor Sinnock.