Shiva Purana
पार्थिवेशार्चनं कृत्वा तपः परमदुष्करम् ॥ चकार वीरसेनो वै वर्षाणां द्वादशावधिः ॥ ३५॥
Worshipping the earthen image of the lord, Vīrasena performed a severe penance, lasting for twelve years.
english translation
pArthivezArcanaM kRtvA tapaH paramaduSkaram ॥ cakAra vIraseno vai varSANAM dvAdazAvadhiH ॥ 35॥
hk transliteration by Sanscript