Whakaotihia te rerenga e whai ake nei: I te timatanga o te Pakanga o te Tuarima o te Whakawhanaunga, i whakarerea e Deroy te mana o te Rōpū Tuatahi ki te Korona Korona Ludwig o Bavaria ka riro i a ia te mana o te Rōpū Tuatoru i te VII Corps. Ko tenei waahanga ko te 5th, 9th, 10th, me te 14th Infantry Regiments, te 5th me te 7th Light Battalions, nga "Taxis" Dragoons me "Bubenhoven" Chevau-légers, me nga waahanga 18 o nga patu patu. Whai muri i te whakaekenga o Ahitereiria, i mau a Deroy i te taha hauauru o te awa o Isar i te ritenga o Landshut i te 16 o Aperira 1809. I roto i te mahi poto, i ngaro i ia taha 150 ki te 200 i mate me te whara. Whai muri i te whiti o te pou Austrian i runga i te awa i Moosburg, ka hoki ia ma Pfeffenhausen ki Siegenburg. I raro i te whakahau a Marshal François Joseph Lefebvre, i tae atu a Deroy engari kaore i uru ki te
Te Pakanga o Abensberg i te 20 o Aperira.