After the war, Hanthawaddy entered its golden age whereas its rival Ava gradually went into decline. From the 1420s to the 1530s, Hanthawaddy was the most powerful and prosperous kingdom of all post-Pagan kingdoms. Under a string of especially gifted monarchs—Binnya Ran I, Shin Sawbu, Dhammazedi and Binnya Ran II—the kingdom enjoyed a long golden age, profiting from foreign commerce. Its merchants traded with traders from across the Indian Ocean, filling the king's treasury with gold and silver, silk and spices, and all the other stuff of early modern trade. The kingdom also became a famous centre of Theravada Buddhism. It established strong ties with Ceylon, and encouraged reforms that later spread throughout the country.