The market for Old Master paintings has long been considered a sober and serious counterweight to the raucous world of Contemporary art. Demand remains steady and somewhat predictable due to supply constraints and scholarship. Old Master prices go up slower than in other markets, but they don’t come down.

Nonetheless, there are boomlets in this market, and Cranach the Elder is having one. Christie’s recently announced it would sell a court portrait by Cranach in its April 15 New York auction of Old Master paintings. The betrothal picture of Sybille of Cleves, estimated at between $4 million and $6 million, comes to market in the midst of estimate-busting sales for Cranach and a major museum show making the rounds in Europe. Cranach’s newfound popularity (catch him in the opening credits of Desperate Housewives) also points to how collectors’ tastes across all categories — even Old Masters — are changing.

But first, the picture. Sybille was the elder sister of Anne of Cleves. Anne’s more lasting fame came when she was briefly the fourth wife of Henry VIII. Hans Holbein painted Anne’s betrothal portrait. Contrary to popular myth, the ill-fated marriage was not ruined because Holbein was too flattering in his depiction of Ann.

Cranach was the court painter to the Elector of Saxony, a Protestant stronghold, and he produced a number of portraits of Sybille of Cleves, who married the Elector in 1526. Cranach painted three of these betrothal portraits — and we know that Cranach himself did all of the painting on these pictures (one of the reasons it has such a high estimate) because they were for one of his most important clients.

Sibylle is depicted with numerous objects befitting her marriage. The most striking is the jeweled and feathered wreath that sits atop her head. With its drooping frond, the wreath is a token of the young woman’s virtue, and it was presented to her husband during the engagement and wedding ceremonies. For us, it is just a reminder of how tastes and fashion change.

The picture was more than a medieval version of a MySpace page. It was a patchwork of symbolism readily apparent to the 16th-century viewer — some of which we can still decipher today. The dress contains patterns that signify her birthright as a member of the House of Saxony, and the necklace combines letters that announce the joining of two important families.

Unlike Holbein’s picture of her sister, Sybille’s portrait shows a young woman with an abundance of character, which would serve her well in later years when she was left to defend her husband’s lands on her own. “She was certainly not a doe-like submissive,” Christie’s head of Old Master paintings, Nicholas Hall, said. “She was nothing if not a strong personality.”

Cranach’s strong painterly line serves Sybille well. It also seems to appeal to collectors. There’s something modern about Cranach that transcends connoisseurship. “He’s a quirky, mannered renaissance artist,” Mr. Hall said. “He inspires some contemporary artists, most notably John Currin.”

But it’s not just the connection to trendy present-day painters. The whole of the art world is experiencing a shift in what collectors want and how they buy. “Traditional Old Master collectors are looking for non-traditional and non–fusty Old Master paintings,” Mr. Hall said. “People respond to images that are powerful and easily understandable. People make their minds up pretty quickly.”

In Contemporary art, they call it wall power. Other experts consider it a preference for the pretty over the arcane. However it is described, the tendency has surprised Old Master experts and confounded their estimates. In July 2005, Cranach’s “Venus and Cupid” sold at Sotheby’s in London for more than $4 million, nearly twice the high estimate. In April 2006, Christie’s brought in just less than $5 million in New York for “St. Barbara in a Wooded Landscape.” The high estimate was half that.

Then, at the beginning of this year Sotheby’s New York sale saw two Cranachs sell well: one for $4 million, and a second for $5 million. The latter had only been estimated as high as $2 million.

The record price for Cranach is more than $8.6 million. But that was set in 1990, a lifetime ago in current art market terms. (Another Sybille portrait sold in 1997 for $500,000.) This picture is not widely expected to beat the $8.6 million record, but if it sells well, expect to see more of Cranach’s work on the market — and of a quality that could establish a new benchmark.

“The mini-market for Cranach is very strong,” Mr. Hall said. “Something about it speaks to today’s taste.”