Novelists go back in time even when, for future generations, their novels may not appear to be what we call "historical". War and Peace is a novel featuring real historical events and characters (though the historical characters play a smaller part in the novel than the fictional ones). If it is possible to read it now without thinking of it as an historical novel (despite those chapters on the philosophy of history, which many wisely skip), this is because the events of 1805 and 1812 were nearer in time to Tolstoy than he is to us. 

This raises the question: what qualifies a novel to be regarded as "historical"? I have written three novels that centre on events of the Second World War. All three span much of the 20th century (with a passage in one which goes back to the 19th), and all are written, or written in part, by a narrator from the standpoint of the 1980s. When I was working on them, I didn't think of them as "historical novels" but, given that they are all retrospective, even though for my characters events now in the past were then in the present and looking to an unknown future, I suspect that this is just what they are. 

Scott gave Waverley, his novel of the 1745 Jacobite Rising, the subtitle 'Tis Sixty Years Since (he should have said 70, since the novel was published in 1814, but he had written the first chapters ten years previously). The rising was only 26 years before his birth. His father was then a boy in his teens. As a child and youth, Scott knew men who had been "out", as the word had it, in the rising.
The '45 was history, certainly, but he was as close to it as anyone born in 1970 is to the Second World War. Scott drew on history to delight his readers, but also to show how present time has come to be what it is.
The past is, as L. P. Hartley said, another country where they do things differently, and exploring this difference is one of the things that may attract the novelist. There is a fine moment in Alfred Duggan's novel about Cerdic, the first king of Saxon Wessex. Duggan has him as a Romanised Briton who, after misfortunes and adventures, becomes leader of a Saxon war-band. Early in the novel, he is reading Ovid in the courtyard of his father's villa when word comes of a Saxon raid. He puts down the book and picks up his sword, and observes, casually, "I think that was the last time I read a book." In that brief observation, the reader has a moment of illumination, catching the transition from Rome to Barbarism. This is something the novelist can do better than the historian.

But if the past is that other country, it is also a place that in certain respects is much like ours. Human nature does not change, though ideas and practices do. People are always subject to the same emotions: love, hate and fear. The Seven Deadly Sins offer the same temptations, and men are driven by ambition, idealism or the desire to exercise power, in any and every age. By turning to the past, free from the busy distractions of the present, the novelist gains the advantage of perspective.

There are essentially two sorts of novel, the open and the closed, even if many straddle the frontier that divides them. The closed novel is self-sufficient, free of the influence of public events. In the open novel, such events become characters in the action. The open novel is exposed to the winds of the world, its characters actors in history or victims of history. Given the difficulty of understanding the confusion and turbulence of the ever-changing present, it is natural that authors drawn to the open novel should turn to the past. Hence, in our present uncertainties, the attraction of the historical novel and the vogue it once again enjoys. Meanwhile, the Waverley novels that delighted several generations wait on the shelves to be discovered by those who have never known them, to be read again by those who, like Virginia Woolf, already love them.