Some of these panzer divisions had quite a large proportion of Panzerkampfwagen I in them, a tank that was never intended for combat. After the invasion of Poland in 1939, the old divisions were partially reorganised (adding a third battalion to some infantry regiments or alternatively adding a second regiment of two battalions). Around this time, the newly organised divisions (6th through 10th) diverged in organisation, each on average with one tank regiment, one separate tank battalion, one or two infantry regiments (three to four battalions per division).