Editing Constantijn Huygens (section)

===Education of his sons and the new royal Prince===
In 1645, his sons Constantijn Jr. and Christiaan began their studies in Leiden. In these years Prince [[Frederick Henry of Orange]], Huygens' confidante and protector, became increasingly ill, and died in 1647.  The new [[stadtholder]], [[William II of Orange]], greatly appreciated Huygens and gave him the estate of [[Zeelhem]], but he died too in 1650.

The emphasis of Huygens' activities moved more and more to his presidency of the Council of the house of Orange, which was in the hands of the young Prince inheritor, a small baby. He traveled frequently during that time, in connection with his work. There were however strong disagreements between the baby's widowed grandmother [[Amalia of Solms-Braunfels|Amalia van Solms]], and its widowed mother (her daughter in law) [[Mary, Princess Royal and Princess of Orange|Mary, Princess Royal]], (4 November 1631 – 24 December 1660, aged 29) on even the name for christening the Dutch-English Royal newborn.
 
In 1657, his son Philips died after a short sickness during his [[Grand Tour]] while in [[Prussia]]. In that same year Huygens became seriously ill, but healed in a miraculous manner.

In 1680, Constantijn Jr. moved with his family out of the house of his father. To stop the gossiping that started shortly afterwards, Huygens wrote the poem ''Cluijs-werck'', in which he shows a glimpse of the latter stages of his life.