A321 Captain reported an undocumented transport of Dangerous Goods. Dangerous Goods were loaded onboard without the flight crew receiving and completing the required Dangerous Goods Form prior to gate departure.

Narrative

I was the Captain on a flight running late out of ZZZ to ZZZ1. The brief came out late due to the ramp; I believe was short staffed; and the Tug Driver stated that it would be a few minutes for them to enter the load numbers. As the brief was printed out the FO (First Officer) briefed me on the numbers as I taxied the aircraft. We completed our Before Takeoff Checklist and proceeded to ZZZ1. As we reached cruise altitude I had a chance to examine the brief for myself and noticed that it indicated restricted articles Dangerous Goods in the forward cargo compartment. We did not receive a notification from Dispatch or the Ramp indicating that we need a Dangerous Goods form and the FO; or myself; did not catch the restricted articles on the brief.Fatigue may have been a under lying factor in this event. We had landed in ZZZ at a little after XA:00 that morning and had a short day sleep at ZZZ. I had slept well and felt rested but as we were preparing for the flight our inbound aircraft was late due to [an event] at ZZZ and delayed our departure.Normally I receive a notification from Dispatch; alerting me that restricted articles will be loaded and that a Dangerous Goods Form will be required. More closely monitoring the FO on the briefing.