01 May 1909,
In San Sebastian, the red flag was first placed. The Federation of Workers’ Associations in the Guipuzkoan capital displayed the red flag throughout the day. The association delegations held a meeting on Employee Day. They asked for amnesty for the prison or judicial workers for an eight-hour day and better working conditions. They also came to the Civil Government with a document containing those requests. The Federation of Workers’ Associations played an active role in disseminating progressive ideas in Donostia.
Source:
Miguel Usabiaga, Donostia rebelde.