The Pashupatinath Temple is a famous 5th century Hindu temple dedicated to Lord Shiva (Pashupati). Located on the banks of the Bagmati River in the eastern part of Kathmandu, Pashupatinath Temple is the oldest Hindu temple in Kathmandu. It served as the seat of national deity, Lord Pashupatinath, until Nepal was secularized. However, a significant part of the temple was destroyed by Mughal invaders in the 14th century and little or nothing remains of the original 5th-century temple exterior. The temple as it stands today was built in the 19th century, although the image of the bull and the black four-headed image of Pashupati are at least 300 years old. The temple is a UNESCO World Heritage Site. Shivaratri, or the night of Lord Shiva, is the most important festival that takes place here, attracting thousands of devotees and sadhus.[citation needed]

Answer this question, if possible (if impossible, reply "unanswerable"): When was the Pashupatinath Temple built?
5th century