During the following several years Kerll was somehow able to combine travelling with working in Brussels without losing his job. First, Leopold Wilhelm sent him to Rome to study under Giacomo Carissimi. This was around 1648/9; Kerll must have met Johann Jakob Froberger and might have studied with him. Returning to Brussels for a brief time, he left again in the winter of 1649-1650, travelling to Dresden. He also attended the wedding of Philip IV of Spain and Marie-Anne of Austria, visited Vienna several times in 1651 and 1652 and spent some time in Göttweig and Moravia. Abraham van den Kerckhoven substituted for Kerll while he was away and ultimately succeeded him in 1655, when Kerll left.