Complex sentence: Cunningham took his seat on the Court on February 14,1912, the date Arizona entered the union and was Chief Justice from January 1918 to December 1929 when he was succeeded by Henry D. Ross.
Split into simpler sentences: Cunningham took his seat on the Court on February 14,1912, the date Arizona entered the union. He served as Chief Justice from January 1918 until December 1929 when he was succeeded by Henry D. Ross.