Picard Delta One was a holographic program devised by Captain Jean-Luc Picard in 2369 to deceive the sentient hologram, James Moriarty, into releasing his control over the USS Enterprise-D.
The program, built around Moriarty's own holographic Enterprise-D, in which he had trapped Picard, Data, and Reginald Barclay, was intended to make Moriarty believe that he had been successful in his attempts to recover the Countess Regina Barthalomew and escape the holodeck, and had departed the Enterprise-D in the shuttlecraft Sakharov. In reality, the two holograms remained within the program, one designed to allow them to explore without limit.
After Moriarty's "escape", the program was saved to a tech cube and was left to run continuously on its own power source. (TNG: "Ship In A Bottle")