Complex sentence: She was promoted to full professor in 1921, and became chair of the philosophy department in 1924, a position she held until her retirement in 1953 and in 1954 she received an honorary Doctor of Humane Letters (LHD) from the college.
Split into simpler sentences: She was promoted to full professor in 1921, and became chair of the philosophy department in 1924, a position she held until her retirement in 1953. In 1954 she received an honorary Doctor of Humane Letters (LHD) from the college.