Complex sentence: The first significant foray into psychosurgery in the twentieth century was conducted by the Portuguese neurologist Egas Moniz who during the mid- 1930s developed the operation known as leucotomy.
Split into simpler sentences: The first significant foray into psychosurgery in the twentieth century was conducted by the Portuguese neurologist Egas Moniz. During the mid- 1930s he developed the operation known as leucotomy.