well established 
adjective
Firmly established, especially because of a long existence: his father was now well established in his career a well-established tradition...
- The well-established tradition for farmers to take the livestock for sale to their local auction market is now under threat.
- They are all in well-established, popular community meeting centres, such as village shops and post offices.
- The easy fusion of land, industry, and commerce was a well-established English tradition.