Written sources of 1426 and 1523 mention a worship site near Mosėdis, which nowadays is deemed to be related with the Šilale Oak and the Great Stone. The stone with a hollow was found and archaeologically explored in 1970. Research has shown that the sacred place has been used for a long time. Water-filled bullauns is a common feature of Couronians and the majority of other Balts – the special water, such as of the first thunderstorm or snow, or the dew of a festive morning; next to the stone, holy fire was lit. It is believed that the combination of these two elements – water and fire – is the heavenly deity Thunderer (Pērkons, Perkūnas), who provided good harvest and prosperity.