Oda Nobunga was a fellow trying to unify Japan, thought of as a local buffoon in his early days,
who was assassinated. He's celebrated as a hero today.
So, the Inuyasha story takes place before he went against the government, I suppose.

Feel free to read more on Wikipedia about him.

From http://en.wikipedia.org/wiki/Oda_Nobunaga:

As Nobunaga conquered Sengoku period Japan and amassed a great amount of wealth, he progressively supported the arts for which he always had an interest, but which he later and gradually more importantly used as a display of his power and prestige. He built extensive gardens and castles which were themselves great works of art. Azuchi castle on the shores of lake Biwa is said to be the greatest castle in the history of Japan, covered with gold and statues on the outside and decorated with standing screen, sliding door, wall, and ceiling paintings made by his subject Kano Eitoku on the inside. Nobunaga is remembered in Japan as one of the most brutal figures of the Sengoku period.