In Old Swedish, the verb varda ‘become’ was used both as a copula and as a passive auxiliary. During the 1300s, a period of close contact with Middle Low German, the verb blîven ‘remain’ was borrowed into Swedish as bliva. Despite the difference in meaning (‘become’ vs. ‘remain’), the use of bliva increased, and by the end of the 1500s it was used in all constructions where varda was originally found. We study this development in a collection of Swedish texts from 1487 to 1585. The first occurrences of the ‘become’ meaning are found in constructions with adjectival complements, in particular in the highly frequent phrase bliva död ‘become dead (die)’. Once bliva had acquired the meaning ‘become’, it could also be used as a passive auxiliary, which led to a rapid increase in occurrences and subsequently to bliva replacing varda in all contexts.