From A History of Iran: Empire of the Mind, by Michael Axworthy (Basic Books, 2016), Kindle Loc. 2645-58:
Succession was a common difficulty for many monarchs. In Europe, the problem was that every so often a ruler could not produce a son. This could create all sorts of difficulties—attempts at divorce (Henry VIII, for example), attempts to secure recognition for the succession of a daughter or more distant relative, disputes over succession resulting in war. In the Islamic world, the problem was different. Polygamy meant that kings did not normally have a problem producing a son, but they might, on the contrary, have too many sons. This could mean fierce fighting among potential heirs and their supporters when the father died. In the Ottoman Empire such battles were institutionalized—rival sons who had served their father as provincial governors would, on hearing of his death, race for the capital to claim the throne. The winner would get the support of the janissaries, and would then have the other sons put to death. Later, the Ottomans adopted a more dignified arrangement, keeping the possible heirs in the Sultan’s harem palace until their father died. But this meant they would have little understanding of or aptitude for government, and the new practice helped to increase the power of the chief minister, the vizier, so that the vizier ruled effectively as viceroy. It was a conundrum.
Many fathers have disagreements and clashes with their sons, and history is full of feuds between kings and their crown princes. Abbas was no exception; he had come to power himself by deposing his father. Following the Ottoman precedent again, he imprisoned his sons in the harem for fear that they would attempt to dethrone him. But he still feared that they might plot against him, so he had them blinded, and he had one of them killed. Eventually, he was succeeded by one of his grandsons. The unhappy practice of keeping royal heirs in the harem was kept up thereafter by the Safavid monarchs.