Queen Seondeok of Silla builds, near Gyeongju, an astronomical observatory (Cheomseongdae) one of the oldest in East Asia.

Songtsän Gampo builds the first palace on the site of the Potala Palace in Lhasa.

The Muslims overthrow the rulers of Ghassan, which had remained a Roman vassal state.

Xuanzang sets out in 637 from Lumbini to …

…Kusinagara, the site of Buddha's death, before heading southwest to …

…the deer park at Sarnath, where Buddha gave his first sermon, and where Xuanzang finds fifteen hundred resident monks.

Traveling eastward, at first via Varanasi, …

…Pataliputra (Patna) and …

…Bodh Gaya.

He is then accompanied by local monks to …

…Nalanda, the great Buddhist university of Indian state of Bihar, where he will spend at least the next two years in the company of several thousand scholar-monks, whom he praises.

Xuanzang will study logic, grammar, Sanskrit, and the Yogacara school of Buddhism during his time at Nalanda.v