Shiva Purana
ततश्शिरांसि छित्त्वा च पूजनं शंकरस्य वै ॥ प्रारब्धं दैत्यपतिना रावणेन महात्मना ॥ ७॥
Then the ambitious Rāvaṇa, lord of Daityas, began to worship Śiva by cutting off his heads.
english translation
tatazzirAMsi chittvA ca pUjanaM zaMkarasya vai ॥ prArabdhaM daityapatinA rAvaNena mahAtmanA ॥ 7॥
hk transliteration by Sanscript