Before Aegon the Conquerer arrived Westeros, it was called the seven kingdoms. It was ruled by seven houses(kings): Stark, Arryn, Tyrell, Martell, Tully, Greyjoy and Lannister. The house Baratheon was born during the Wars of Conquest. Its founder, Orys Baratheon, was rumored to be Aegon the Dragon's bastard brother. Orys rose through the ranks to become one of Aegon's fiercest commanders. When he defeated and slew Argilac the Arrogant, the last Storm King, Aegon rewarded him with Argilac's castle, lands, and daughter.
The Targaryens are the blood of the dragon, descended from the high lords of the ancient freehold of Valyria. Aegon the Dragon's ancestors espcaped the Doom of Valyria to settle on Dragonstone, from where with his sisters Visenya and Rhaenys sailed to conquer the seven kingdoms.
The Targaryen family tree is shown as following link:
http://upload.wikimedia.org/wikipedia/en/7/7e/Targtree2.pngSince I don't know what do you mean 少龍主, I can't answer your question now.
韋賽里斯,雷加和丹妮利絲 are brothers and sister, Offsprings of Aerys the Mad King and his sister and wife, Queen Rhaella.
PS: All the information I typed above can be found on the net. Do use google and look at previous threads before asking any questions about relationship between people please.
