coh IIII Gall
V. S. L. M.
What’s particularly interesting about this altar is that it is inside the walls of the fort proper, in an area that might conceivably have been a shrine, rather than in or on the exterior walls, as is common all along the forts and guard posts associated with Hadrian’s Wall.After preliminary excavation, the bottom half of a second alter was discovered, suggesting that there may have been a more formal shrine. The second altar was dedicated to Dolichenus by a prefect of the Second Cohort of Nervians, a Vindolanda regiment that later moved to the fort at Whitley Castle in the third century. There were animal remains as well, which suggests that there may have formal sacrifices and feasts in the vicinity.
We know from the Vindolanda tablets that Sulpicius Pudens was the commanding officer of the Roman regiment stationed in Vindolanda during the third century C.E. It would have been fairly typical for Sulpicius Pudens to have had the altar created and dedicated to the deity in fulfillment of an oath. It would also appear that this is the same Pudens who dedicated a smaller altar on another wall of the fort.
The Romans enlisted soldiers from all over the empire and those men tended to bring their gods with them, and adapt the local deities as well. Jupiter Dolichenus was a deity that Romans in Anatolia adopted; there, he is associated with a hill outside the Turkish town of Dülük, (then known as Doliche). He began to be popular among Roman soldiers stationed nearby during the beginning of the second century C.E. From Duluk, the soldiers carried him all over the empire—leaving hundreds of inscriptions and altars dedicated to him. In Anatolia, Dolichenus was a deity associated with weather, known to the local Semitic speakers as Hadad, and to the Indo-European Hittites as Teshab. The sobriquet “Jupiter” was added by Roman worshipers who identified Dolichenus as an avatar of Jupiter.
You can find more here and here. There are several other altars, and stone building inscriptions at Vindolanda, but nothing as dramatic as this.