In Norse mythology, Thor is a hammer-wielding god associated with thunder, lightning, storms, oak trees, strength, the protection of mankind, and also hallowing, healing and fertility. The cognate deity in wider Germanic mythology and paganism was known in Old English as punor and in Old High German as Donar, stemming from a Common Germanic punraz (meaning "thunder"). Ultimately stemming from Proto-Indo-European religion, Thor is a prominently mentioned god throughout the recorded history of the Germanic peoples, from the Roman occupation of regions of Germania, to the tribal expansions of the Migration Period, to his high popularity during the Viking Age, when, in the face of the process of the Christianization of Scandinavia, emblems of his hammer, Mjolnir, were worn in defiance and Norse pagan personal names containing the name of the god bear witness to his popularity. Into the modern period, Thor continued to be acknowledged in rural folklore throughout Germanic regions. Thor is frequently referred to in place names, the day of the week Thursday ("Thor's day"; Old English Thunresdag, Thunor's day); German "Donnerstag" (Donar's day); Dutch "Donderdag", bears his name, and names stemming from the pagan period containing his own continue to be used today.