Long-established

First, the employments must be well known and long established in the neighbourhood ;

Source: wiktionary

The age in which we live is remarkable for searching out, and sifting to the bottom, the most long-established opinions which have come down to us.

Source: wiktionary

In the Edinburgh area, Leith and neighbouring Granton have only one terminal station where formerly there were four, and the long-established ferry from Granton to Burntisland, the history of which stretches back to the dawn of Scottish railways, is no more.

Source: wiktionary

Some long-established trains have disappeared from the new timetables, including the through trains between Birkenhead and Margate, and York and Bournemouth. These will be restored in May, [...].

Source: wiktionary