The games with gold of the first xbox and xbox 360 are mine forever independent of the gold...

I believe OG Xbox Games With Gold titles are considered Xbox 360 content and fall under the same rules; that is, the title is yours to keep forever. Only native Xbox One GWG titles require that you maintain the subscription to keep access.

They are yours to keep my friend

Hi there,

Xbox 360 games acquired via Games with Gold will continue to work even if you don't have a Gold subscription anymore.

I'm not sure about the games for the original Xbox though. For Xbox One games an active Gold subscription is required.

For more information see this link:
https://support.xbox.com/my-account/xbox-live-membership/games-with-gold-faq

With Xbox 360 titles you will own the games in perpetuity regardless of if your Xbox Live Gold subscription is active or not.

With Xbox One titles you will be able to play the game as long as your Xbox Live Gold subscription is active.

Original Xbox titles are much like Xbox One games and purchased through that store under backwards compatibility so the same rules as Xbox One titles apply and you will need to have an active Xbox Live Gold subscription to play those.

The Xbox 360 titles are different because of how that store was engineered and handled licensing, and the limitations of that store are why the "purchases" are permanent. Since the OG Xbox titles are purchased via the Xbox One digital storefront, they do
not have the same stipulations as the 360 titles.

Please note that I have not verified this myself, but a friend of mine tested this and was unable to play the backwards Xbox titles without an active Gold subscription, so if there is conflicting information, please feel free to correct me.