In this article the use of prepositions in combination with the infinitive in Old Swedish (OSw) and Early Modern Swedish (EMSw) is investigated. The preposition til ('to, at') is often used in combination with an infinitive clause containing the infinitive marker at in OSw and EMSw. Sometimes the infinitive marker is omitted and til alone is standing in front of the infinitive. The main goal of the article is to discuss whether, in such cases, til should be regarded as an infinitive marker or as a preposition. It has often been claimed that til in combination with a bare infinitive should be analyzed as an infinitive marker. The data for the analysis is taken from 40 OSw and EMSw texts containing more than 3300 infinitive clauses and it is shown that the infinitive marker at is sometimes omitted after other prepositions than til. This, however, does not mean that these prepositions are infinitive markers since the prepositions governing bare infinitives are only found in very specific lexical or semantic contexts whereas the infinitive marker at can be found in all contexts without any distributional restrictions. The proposed analysis suggests that til is not to be regarded an infinitive marker in OSw, and that it is only when the combination of til and at is grammaticalized into an infinitive marker in EMSw that til is also being used as such. Thus, the use of til as an infinitive marker is depending of the earlier grammaticalization of til at into an infinitive marker.