From their plates taken with the 200-inch telescope Baade and Minkowsky (1954) identified Cygnus A as "an extragalactic affair, two galaxies in collision", drawing on the work of Spitzer and Baade (1951). Their plates showed a mpg = 17 extragalactic nebula with two bright nuclear condensations, separated by 2 arcseconds, in position angle 115°. Despite the low galactic latitude, many extragalactic nebulae were seen in the vicinity of the Cygnus A galaxy. Baade and Minkowsky however could not simply classify the Cygnus A galaxy. Minkowsky was also puzzled by the double morphology of the radio source (Schmidt 1995). In 1957 he mentioned the interaction scenario again, and dealing with the radio components being located outside the optical galaxy he conjectured that "tidal filaments in some systems extend much farther" (Minkowski 1957). From Baade's original 200-inch plates Matthews et al. (1964) subsequently classified the galaxy as cD3 following Morgan (1958), with a double nucleus, and being the brightest member of a richness class 2 cluster. The cluster issue was taken up again by Spinrad and Stauffer (1982) who determined redshifts for six nearby E/S0 galaxies, and found four of these to be members of the Cygnus A group. The true richness class determination awaits high resolution, deep, wide-field CCD imaging and spectroscopy. Confirming earlier work by Yee and Oke (1978), the galaxy itself was found to have a normal (off-nuclear) gE or cD optical spectrum, and to be large: a reddening-corrected r(µR = 26) radius of 40 arcsec (40 kpc, for H0 = 75) was measured (Spinrad and Stauffer 1982). The rather shallow surface brightness profile was however not confirmed by Pierce and Stockton (1986), Carilli et al. (1989), Vestergaard and Barthel (1993) and Stockton et al. (1995). These authors obtained good fits to the radial surface brightness profiles, at optical and near-IR continuum wavelengths, with de Vaucouleurs (1948) r1/4 profiles, out to large radii. In that sense, Cygnus A may be different from the classical cD galaxies in rich clusters (e.g. Oemler 1976), having extensive envelopes. This recalls Thuan and Romanishin (1981) who found that brightest galaxies in poor clusters - of which Cygnus A may be an example - differ from cD galaxies in lacking such envelopes. This difference is commonly attributed to the low tidal stripping rate in poor clusters, and it will be of interest in this respect to determine the true Cygnus A cluster content. Against identification with a cD galaxy is the observation by Owen and Laing (1989) that cD galaxies tend to harbor twin jet FRI radio sources, and not classical double FRII sources such as Cygnus A, as well as the fact that the emission line properties of Cygnus A are somewhat atypical for cD galaxies (Baum et al. 1992). As long as new data do not show otherwise we prefer that Cygnus A be classified as the brightest and largest elliptical galaxy in a poor cluster, but again, the true cluster content awaits determination.