Grenzers were the successors to the irregular army of Pandurs, which were also raised as a militia by the Habsburgs in the 18th century to defend the border with the Ottomans and also used as skirmishers in the Seven Years' War. However, by the time of the Napoleonic Wars, troops from the Frontier were now formed into more regular line infantry regiments, but were considered by the Austrian generals as something between light and line infantry. They were given training in marksmanship, skirmishing and the basics of linear tactics. At the start of the war, the 18 Grenz infantry regiments formed about a quarter of the Habsburg army.