Various classes of Vajrayana literature developed as a result of royal courts sponsoring both Buddhism and Saivism. The Mañjusrimulakalpa, which later came to classified under Kriyatantra, states that mantras taught in the Saiva, Garuda and Vaisnava tantras will be effective if applied by Buddhists since they were all taught originally by Manjushri. The Guhyasiddhi of Padmavajra, a work associated with the Guhyasamaja tradition, prescribes acting as a Saiva guru and initiating members into Saiva Siddhanta scriptures and mandalas. The Samvara tantra texts adopted the pitha list from the Saiva text Tantrasadbhava, introducing a copying error where a deity was mistaken for a place.
Try to answer this question if possible (otherwise reply "unanswerable"): The royal courts sponsored both Buddhism and what?
Saivism