Complex sentence: By 1961, Varian Arabians had a small number of mares, the most notable being the Witez II daughter Ronteza, who was out of the mare Ronna.
Split into simpler sentences: By 1961, Varian Arabians had a small number of mares. The most notable of her early champions was Ronteza, a daughter of the stallion Witez II out of the mare Ronna.