I te wā i riro ai te Whenua o Batavia hei Kīngitanga o Holland i te tau 1806, ka manakohia a Van Merlen e Kingi Louis, ā, i whakaingoatia ia hei Lieutenant Colonel i roto i te Royal Guard Hussars i te 23 o Oketopa 1806. E toru nga ra i muri mai ka haere ia me te ope taua o te Netherlands ki Tiamana ki te tautoko i nga ope French i te pakanga ki Prussia
He aha? I kite ia i te mahi tata ki Ertzen i te 7 o Noema 1806 ka peia e ia te roopu Prussian ki Hamelin. Heoi, i puta he tautohetohe i waenga i a Louis me tona tuakana a Napoleon i hua ai te Royal Guard i whakahokia ki The Hague me te kore e kite i etahi atu mahi.