Nah....Ned did right.
Jon is basically the rightful ruler of Westeros. His claim even supersedes Dany's claim, assuming Rhaegar married Lyanna. The Baratheons took the Iron Throne and disinherited the Targaryens but, there are plenty of houses that would support the Targaryens coming back into power. That is a secret that could get entire families clapped up. Cersei had all of Robert's b*stards killed. You think they wouldn't have had Jon gunned up and clapped quick
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Do you remember all the dumb shyt Cat did with Robb?
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Would you really trust her with that secret? Plus, wives are supposed to hate b*stards. If Cat knew Jon was really her nephew-in-law, she would ease up on him, start liking him. Likely grow to love him. That would look weird to other people in Westerosi society. Certainly to the Lannisters when they came to Winterfell. And people will start wondering and asking questions, which is bad for Jon. Jon was also envious of Robb being the future lord of Winterfell and him being destined for nothing. Telling him that he was the true heir to the Iron Throne would have him feeling himself. And one day, it would slip out around the wrong people. It was better for Jon for everyone to think he was a b*stard and treat him like one.
You also can't be giving out lands like that to your other sons. It weakens the power of the House. If every time a father in that house had an extra son, and gave him a piece of land, eventually the inheritance to the first son would be nothing. That's why it's set up for the other sons to get nothing
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Maybe they can become a Maester, a Knight, a member of the Night's Watch or stay at the castle and be the right hand man to their brother. Also.........giving land to siblings could mean that hundreds of years later, that sibling's descendants may go to the war with the main family. That's what the Greystarks (descendants of a Stark Lord's brother) did to the Starks. That's why the Greystarks are extinguished, dead and gone. The Karstarks are former Starks too. They looking like they might betray the Starks as well. This is also essentially what the Baratheons did to the Targaryens. The Baratheons are descendants of the Targs....descendants of Aegon the Conqueror's b*stard brother. More recently, Robert Baratheon's grandmother was King Aegon V's daughter. So, when Robert rebelled against the Targs, he used his Targaryen heritage as a justification to be King. Giving lands away to your siblings/b*stard brothers is cool today but, you don't know what their children and their grandchildren and their descendants will do to yours.