Tyskland is just the translation of Deutschland, in danish.
Germanic tribes is almost all that moves around from the northern parts of Scandinavia, to Germany and the Netherlands.
There were (are ? lol) other tribes like Suebes, the Chattes a.s.o. but all merged with the later Franconian or Alemanni as Skybird wrote.
There were some germanic tribes in the northern parts of what is Germany today (but was'nt then), a tribe called Angeln or Angles, and then there certainly were the Saxons. When they tried to "invade" England (was more of a long-lasting movement), they became to be known as the Anglo-Saxons, forming parts or shires like Sussex or Wessex, as abbreviations of new Western or Southern Saxony.
When the Normans came in 1066, some of the older names stuck until today. From the language, some say that english is closer to the original "germanic" tongue of those tribes, than in today's Germany, certainly due to the isolation and on the other hand the ongoing interaction that took place on the continent.
The 'th' was a typical germanic phoneme, e.g. the gathering of chiefs to deal and speak right regulöarly, was called the "Thing", no joke.
A certain Mr. H. from Austria never understood why England declared war to Germany in WW2, by his own racial ideology they were the closest brothers
