Java forms the political, economic, and cultural core of the modern state of Indonesia. In the premodern period, the island constituted a crossroads of contacts across the maritime routes connecting South Asia to East Asia through Southeast Asia. Java has played an important role in the exchange of knowledge that mainly took place between the 5th and 15th centuries CE, referred to as “Indianization,” “Sanskritization,” or “Indicization,” as its Malayo-Polynesian language-speaking societies received—and “localized”—Sanskrit language as well as Indic legal norms, aesthetic and political paradigms, and religions like Śaivism, Vaiṣṇavism, and Buddhism. Śaivism was one of the most important religious traditions of what is now generally termed “Hinduism,” focusing on the cult of Śiva as the paramount god. Prior to the widespread Islamization of Java and the European expansion, Śaivism was patronized by the Javanese political elites and adopted by the common people too. It was also the main religion in the neighboring island of Bali, which has survived up to nowadays as the reformed version of “Balinese Hinduism” that came to the fore from the early 20th century onward. The importance of Śaivism for the history and culture of premodern Java and its continuation through the early modern to the modern period (during which Islam became predominant) cannot be stressed enough. Śaiva symbols and ideas played an important role not only in the religious sphere but also in artistic and political life, influencing the local concepts of kingship and shaping the iconography of many temples and artistic remains.