Complex sentence: She turned down Philip II's own hand in 1559, as well as for several years entertaining the proposal of King Eric XIV of Sweden and negotiating to marry Philip's cousin Archduke Charles of Austria.
Split into simpler sentences: She turned down Philip II's own hand early in 1559, and for a time entertained the proposal of King Eric XIV of Sweden. For several years she seriously negotiated to marry Philip II's cousin Archduke Charles of Austria.