Razib Khan mentioned her death at Unz:
I was aware that Colleen McCullough was ill, so sadly it is no surprise that she has died. To many McCullough is known for her Masters of Rome series. I particularly think that the first two books in the series, The First Man in Rome and Grass Crown were exceptional. The later novels cover the career of Julius Caesar and his heirs (both Augustus and Antony), which are rather well known to us. In contrast the life and times of Gaius Marius and Lucius Cornelius Sulla are not familiar to many modern people. In fact it is likely that their names would not ring a bell with the vast majority of people due to the decline of the classical education (which was the province of a narrow elite in any case when it was in vogue). But these were significant figures in their time whose influence echoes down the generations.
I never read The Thorne Birds, but I did enjoy the first three Rome novels. The Masters of Rome series inexplicably fell off a cliff with the fourth novel, Caesar’s Women, but the first three were both entertaining and educational. I even suspect, to a small extent, they may have had some influence on my choice of Rome’s Social War as a conceptual start to Arts of Dark and Light.