By 1967, Fiat was leading the European market, and its 50th anniversary was coming up. For the occasion, a new series was developed in Turin with more innovative characteristics than earlier models. The new series would be based on the Diamante series, and the name chosen was "Nastro d'Oro" or "Gold Ribbon", marking the "Golden Anniversary" of Fiat's "marriage to the land".

The appearance was a strong evolution of the Diamant series, again penned by Pinninfarina, with the longitudinal ribs of the engine cover now more predominant, and running though to the nose conferring lightness and movement. The colors were slightly changed as well, with a lighter orange for the bodypart, and blue for the mechanical parts, which gave the impression of a dynamic and modern machine. 

The new series wasn't only a styling exercise though. The series introduced new upgraded engines, all now with direct injection and rotary injection pumps, and all but the smallest reverting to a stressed crankcase design. Improved driving ergonomics, a number of new safety features including a lock preventing starting the engine while in gear, new 12 volt electrical system, upgraded gearboxes with synchronizers, and the control-matic three-point hitch now standard on all models, are just a few of the technical features to mention.

Some sources tell, that all models at launch had the option of a Frutteto, Vigneto and Granluce variant, though this has been difficult to confirm.

The first models of the "Nastro d'Oro series"/"Gold Ribbon series", were put into production in 1968.

The 850 was introduced in 1969, engined and manufactured by OM.

The 850 together with the 650 and 750, would be the last tractor sold under the OM brand, with the OM company being merged into the Fiat group in 1975, including their truck and bus division.
1975 would also be the last year for the 650, 750 and 850/850S, being replaced by the first 80-series models 780 and 880.
But until 1975, the 850 and other aforementioned models, were sold in Italy under the OM brand, while on the international market, it was sold under the Fiat brand. Except from France, were all models were still sold under the Someca brand.

All models used a stressed chassis design, with the engines cast-iron crankcase being part of the tractors backbone. 

The gearbox in the 850 and 850S, was a completely new fully synchronized gearbox with 12 forward and 4 reverse gears. The positioning of the gearlevers were new as well, having found their way to the instrumentpanel, reaching out from under the steering wheel. A placement that would come to define the driving experience of all medium and large size Fiat tractors, until the Ferrari-inspired gated shifter in the 1990 Winner-series.
PTO now had two speeds of 540 and 1000 rpm, and locking differential was standard on the rear axle.

The 850 used OM's CO3/80 four cylinder watercooled, direct injected diesel engine. An enlarge version of the engine found in the 780. With a displacement of 4.940cc, the engine developed 85 hp at 2.200 rpm and 318 nm at 1.200 rpm. Later managing 90 hp as the 850 Super.

The Gold Ribbon Series tractors enjoyed even greater success than its predecessor, being recognized for their new design, engines and features.
In 1968 alone, when the European market was contracting, Fiat produced a total of almost 60.000 tractors, 42.000 of which in Modena alone, 5.000 more than the previous year. That year also saw the production of the 500.000th Fiat tractor since 1918.