The painting cannot be assigned an exact date.

这幅画的年代确定不了。

《牛津词典》

We can now say that this painting by Leonardo da Vinci was painted to commemorate the birth of the second son of the Mona Lisa, which helps us to date it more precisely to around 1503.

现在，我们可以说罗纳尔多·达芬奇的这幅画作是为了纪念蒙娜丽莎第二个儿子的降生而作。这帮助我们将作画时间精确到1503年。

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Reformation is required by the social actuality, creating painting of up-to-date characteristic and realistic spirit is the final aim for artist to imitate classical art.

“为新”是现实和时代所趋，创作出具有时代特色和现实精神的绘画是画家师古的最终目的。

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By 1574 she had a grown daughter, in which case the painting would date from the 1560s.

ECONOMIST: Portrait of a lady and her daughter

More than 2, 000 people visited Hull's Ferens Art Gallery last weekend to see David Hockney's biggest painting to date, Bigger Trees Near Warter.

BBC: Hockney��s largest painting draws huge crowd in Hull

It is considered a self-portrait and along with the painter's red signature at right, the sanguine "XX" insignia at far left, and the painting's prospective date suggests Ensor's intent to cast himself as the true prophet of the art to come.

WSJ: A Macabre Kingdom of Masks | James Ensor | Christ's Entry Into Brussels in 1889 | By Mary Tompkins Lewis