I've read once that Belgium has the dubious honor of being the nation that has been invaded the most.
Well, take it from me, I'm a Belgian dude. We've been invaded by everyone... Everyone... really... If there would have been an award for most invaded place we'd be in front of the line alright.

The troubles started even before Belgium was known as Belgium:

There are caves in Belgium with caveman artefacts from the Early Stone age. There are some axes and weapons among them, so presumably the cavemen were invaded from time to time...

In the Late Stone age, some people started building huts and started farming. There probably were some minor invasions by jealous cavemen, who'd rather have a nice, warm hut to sleep in than a cold, damp cave.

After that, in the Bronze and the Iron age, all seemed quiet in Belgium. This was the period when human sacrifice and druidic magic was common practice here. People think twice about invading a country that's full of drunk Kelts who as a passtime go see their druid ritually disembowel one of their own clanmembers.

This period of glory came to an end when, in 57bC. we were invaded by the Head Honcho of the Romans; Julius Caesar. Now... this Julius Caesar was a nasty piece of work. When it became apparent that the Belgae wouldn't submit to Roman authority without handing out a few knuckle sandwiches themselves, the Romans set up a genocide mission. There are several Keltic tribes (a.o. the Eburons and the Aduatucs) that were completely annihilated.

During the Pax Romana, pre-Belgium was invaded by Christianity.

After the Pax Romana, we were invaded by the 'Salische Franken', the Germanen and another tribe of Franken.

In the Early Middle Ages, we only got our butt kicked only once or twice by foreign powers. The rest of the time we spent squabbling among ourselves.

In the... err...'middle' Middle Ages, things got worse. pre-Belgium got repeatedly overrun by various alliances of Barons, Counts, bigshot farmers and important merchants guilds.

In the late Middle Ages, France also got in the fray. Lots of wars... After Death and War, the other two Horsemen of the Apocalypse, Pestilence and Hunger, also invaded pre-Belgium. This was a really bad time. We ended up under Spanish government (Habsburgs). They got kicked out by the Dutch for a while but they soon regained the place.

We, Belgians, came in existence in 1598, when the Habsburgs set us up as an autonomous state as a safeguard against the Dutch.

While the Habsburgs were keeping an eye on the insidious Dutchman, however, the French attacked again, and there were lots of wars, with a climax in 1695, when the capital of Belgium was eradicated by the French.

At this point, I guess we just couldn't be bothered anymore, so we started up a weapons factory, Fabrique Nationale (FN) and started selling weapons to our invaders.

Then, France and Austria invaded us a couple of times.

After that:
26 June 1794. French
23 September 1830. Revolution! We decide we've had enough and Belgium declares it's independence.
2 August 1831. Dutch king Willem I.
3 August 1914. Dutch king Willem II, followed by the Germans and later the English and the French to drive out the Germans.
After that it's Hitler from Germany. He gets kicked out by a.o. the Americans and the British.

Since then, things have been eerily quiet...

I was just thinking I must be mad typing up all this stuff that no-one will read anyway... Well, gotta go now. It's time for bed.

Update: Apparently you _do_ read this stuff... Some of you even seem to appreciate it.

Hehehe... I'm gonna try something now that I've got your attention....

Get a piece of writing paper. Grab a pencil. Any pencil will do. You also need an envelope and a stamp.
Write a formal letter addressed to your local governor, senator, monarch, dictator or president.
Ask them not to invade Belgium.
Tell them we're a country that can hardly be seen without a magnification glass on the average world map.
Point out the absolute absence of any valuable mineral resources whatsoever in Belgian soil.
Enlighten them to the fact that one of our national symbols is, in fact, a statue of a small, peeing boy (Manneken Pis, we call him).
Whatever you write, make clear that we're really not worth invading. Please.

As a fair trade befits, I shall then write to my king (Yes, I know, we still have one of those) and I shall ask him not to attack your country.