Got some updates on my ancestor:
The Regiment was fighting in 1806 in the devastating Battle of Jena on the Prussian side. Luckily my ancestor wasn't enlisted at that time of he would have probably died there as the regiment was nearly completely wiped in the battle. After the capitulation of the Prussians in 1806 Saxony became a French client state and had to bring in 20.000 men into the French Army. One of the newly enlisted recruits must have been my ancestor. Since it was explicitly stated in the family tree that my ancestor took part in the Battle of Wagram I have to assume he was part of the normal Musketeers at that time as only the Musketeers participated there. Thus he was in 1807 with them and marched with the Grande Armée into Poland. There he participated in the nearly 3 months-lasting Siege of Danzig where the Regiment stayed for nearly 1 year afterwards. In 1808 he returned home in Saxony.
In 1809 the War of the Fifth Coalition broke out and Saxony again had its contingents in the French Army, this time marching into Austria. The regiment was part of the Battle of Linz-Urfahr, a minor skirmish between roughly 20.000 Allied and French/Saxon/Wurttembergian troops.
At the Battle of Wagram the Regiment served in the 2nd Brigade of the 2nd Divison of the IX. Corps under Jean-Baptiste Bernadotte who was dismissed by Napoleon after the battle for his poor performance. There my ancestor was probably part of the charge on Deutsch Wagram itself against the Austrian's left flank as the regiment was part of the charge on a small village at that flank whioh ended in Saxons shooting each other as both Saxons and Austrians wore white coats at that time. By night Bernadotte let his men fall back from the village Aderklaa as they were in complete disorder. However Napoleon had ordered a further attack on the left flank so the next morning the Saxon/French Corps had to retake the village again under heavy casualities. The Austrians brought in fresh troops and after 2 hours the Saxon Infantry broke completely and routed the battlefield with Bernadotte not trying to rally them in order. By that time Napoleon in person came over to the left flank of the Battle and fired Bernadotte as his flank was in utter chaos and not usable for the battle anymore. Luckily my ancestors survived this slaughter at Anderklaa.
In 1812 my ancestor must have been part of the Grenadierbataillon "von Spiegel" (which was still part of the Infantry Reg. No5) as he went into Russia with Napoleon. However the "normal" musketeers of the regiment stayed in Northern Germany as garrison troops and only the 2 Grenadier Companies went into Russia. There those two companies took part in many minor skirmishes but did not participate in any major battles (like Smolensk or Borodino). From originally roughly 800 men only 50 returned from the Russian Campaign, with my ancestor being one of them.
Meanwhile in early 1813 the Musketeers who were still garrisoned around Lüneburg in Nothern Germany were completely wiped in the Battle of Lüneburg with their Eagle lost. So from now on only a few Grenadiers remained. They merged with other remaining Saxon Grens into the Grenadier Bataillon von Anger and fought for example in the Battle of Bautzen in the VII. Corps under Reynier.
Finally in late 1813 the Grenadiers were now part of the recreated Gren.Reg. "von Spiegel". Here they participated in a lot of minor battles and ultimately in the Battle of Nations. Still under the command of Reynier's VII. Corps the now famous incident took place: more than 5000 Saxons switched sides along with the Württembergian Cav and my ancestor was one of them
Lastly after the Battle of Nations the Regiment was renumbered once again into the 2nd Infantry Regiment and was part of the march into Flanders. There they remained as garrison until 1817. Right after returning from duty in July 1817 after 10 years of being in the military Ehregott Schmidt married his wife Susanna.
I hope this wasn't too boring and maybe some of you have the time and will to write down stories of their ancestors (if you got one in the Napoleonic Wars or anywhere else). I am very curious if you got some stories to share.